Odd running (miss?)

We got the car started, but it was a bitch to start - lots and lots of cranking- as it had been before. Spraying starter fluid into the intake didn't make much of a difference.
If the fuel pressure regulator is not leaking, it is probably OK. Testing comes down to measuring the fuel pressure with the pump running, while applying varying levels of vacuum to the vacuum port. The FSM and the troubleshooting guide give conflicting numbers for the pressure, but since the troubleshooting guide is biased towards the 2.0 l engine, I would use the numbers from the FSM. Which says 33 - 39 psi fuel pressure with the vacuum hose to the fuel pressure regulator disconnected. As you apply vacuum to the vacuum port of the fuel pressure regulator, the fuel pressure should drop. I have found no reference to the relationship between vacuum and fuel pressure, but the regulators don't usually fail in subtle ways; if the pressure drops as you apply vacuum, I would call it good. The purpose of the FPR is to keep the difference between fuel pressure and manifold pressure constant, so I would expect a 1 psi vacuum change to result in a 1 psi fuel pressure change.
Thanks for this explanation.
Should you find that you need a new FPR, they were used on a wide range of cars and you can find off-brand replacements at O'Reilly, Pep Boys (easy walk for you), NAPA, Rock Auto etc.
That Pep Boys is a service shop only so I could walk there, but I'd be waiting a while. :)
That said, the cold start injector activates every time you try to start the engine (at least as long as the thermo-time switch is below 35°C), so after struggling with a no-start condition for a while you could end up with a flooded engine. This got me once; I had disconnected the ballast resistor for the coil for a round of testing, then forgot to reconnect it. After several attempts at starting the engine, I reconnected the ballast resistor and tried again. The engine was flooded, and It took a bit of cranking at wide open throttle to get it started.
But the no-start happens even when the engine is stone cold and hasn't been started for a few months, overnight or a few days.

Here's what the car has been doing

To get it to start, I start to crank the engine, but it doesn't catch. I've found if I give it a little bit of gas - not a lot and never with a wide open throttle - it will eventually start after 10-15 seconds of cranking. It's literally like a carb'd car where it won't start so you feather the gas pedal a bit to give it some gas and you crank it.

So I really don't think it's flooded engine issue, although it's easy to go there. I can see the cold start injector or any injector bleeding fuel off because of a leak, but all the injectors and the cold start injector have been replaced with NOS parts. And the problem didn't go away. And then there's the engine is stone cold and hasn't been started for a few days, few weeks or months thing.

Bear with me here... below are what starting my car has been like for the past 3+ years (2020 doesn't count because no work was done on the car then).

First, the timing has been checked and all is good. Here's how the car has been the past 3+ years (2020 doesn't count

When I'm able to get the car started:
o I put it in neutral and let it roll backwards out of the garage and down the driveway. When the back wheels get to the street, I put it in reverse and back into the street - I never let the clutch fully out - but have to keep the revs up, or it will stall.

o I then put the car into 1st and have to give it more gas than it would normally need so it doesn't stall when I start moving. I drive about 500' down the street to the stop sign. I put it in neutral and have to keep the revs up so it doesn't stall.

o I put it back into 1st, ease off on the clutch and the car stumbles a little - as if I'm coming off the clutch too fast - but I'm not. Sometimes, it will stall even though I've got the revs up a bit.

o I move away from the stop sign. 0.1 miles later, is a traffic light but by the time the car gets there, it's idling okay and won't stall there or when the light turns green.

o Sometimes, not every time, when I get about 0.6 miles down the road (part of my daily commute when I had one), I come to a traffic light that is almost always red so the car is idling normally for 30 seconds to several minutes (depending on where in the traffic light cycle when I arrive). The light turns green, I put the car into 1st and go to take off, but *sometimes* - not every time, the car stumbles - as if I've let off on the clutch too quickly, but that's not the case. When it does that, I push the clutch back in again, kick the revs up higher than I should have to go back to 1st and start off again and keep the revs up for the next 2 or 3 shifts. After I get 2 more lights down the road, things are fine and I can drive normally.

o Also, the car has an odd miss.... it seems to happen when the engine temperature is between the midway point to 190 and 190 and it seems to be the absolute worst a tick below 190. Below the midway point and the car is perfect.

o It only happens between 3000-4000 rpm and can happen in any gear. The most common RPMs are 3200 and 3800 - which are usually the rev ranges when I'm driving in 3rd or 4th gear. I can make it happen anytime at those 2 RPM's. To make it happen, I slow down a bit so the revs fall to say 2800 RPM and then get on the gas to take it slowly to 4000 RPM. At about 3200 RPM and 3800 RPM it stumbles.

The car feels like the stumble off the line I described above. I don't think it's misfiring as there's no backfire or noise I can easily discern when it happens. I used to say the car feels like I've hit a large bump in the road that only the rear wheels catch although there's no bump and the ride is fine otherwise. It only does it under a load, so just revving the car in my driveway doesn't help or count.

o Or sometimes, it starts right up and acts just like normal and everything is fine. Till I park the car for 30 - 90 minutes and then it doesn't want to start.... see "Here's what the car has been doing"


It's because of these issues we're looking at the FPR or the pump.

I've lived with the issues for awhile, but would really like not to have the issues....
 
Have you checked for vacuum leaks? The big plastic hose that connects the AFM to the intake can crack where the crankcase vent tube is mounted and its difficult to detect.
 
Have you checked for vacuum leaks? The big plastic hose that connects the AFM to the intake can crack where the crankcase vent tube is mounted and its difficult to detect.
I have in the past and can again. But would a vacuum leak cause all the weird problems I've been having and not having?
 
I have in the past and can again. But would a vacuum leak cause all the weird problems I've been having and not having?
It’s not a vacuum leak it would be unmetered air which would lean the engine out
 
I picked up a Fuel Injection Pressure Tester today (https://www.harborfreight.com/basic-fuel-injection-service-kit-64939.html) . We installed it between the fuel line for the Cold Start Valve and the Cold Start Valve.

We measured about 36psi when the fuel pump turned on, but when we turned the key off, the pressure dropped to 0 psi in say less than 10 seconds. I wasn't paying attention to it so the time could have been a few seconds more or less. But my impression was the fuel system would stay pressurized for some number of hours before the pressure drops to 0

Which is correct - should the system stay pressurized for some amount of time or should it drop to 0 that fast?
 
I picked up a Fuel Injection Pressure Tester today (https://www.harborfreight.com/basic-fuel-injection-service-kit-64939.html) . We installed it between the fuel line for the Cold Start Valve and the Cold Start Valve.

We measured about 36psi when the fuel pump turned on, but when we turned the key off, the pressure dropped to 0 psi in say less than 10 seconds. I wasn't paying attention to it so the time could have been a few seconds more or less. But my impression was the fuel system would stay pressurized for some number of hours before the pressure drops to 0

Which is correct - should the system stay pressurized for some amount of time or should it drop to 0 that fast?
The fuel pressure should stay high for some time; way more than seconds. Leaky injectors (main or cold start) will cause the pressure to drop, but you said you replaced all five. I think it is more likely to be the check valve in the fuel pump that is not working. But this would make the engine a bit slower to start, not cause it to run poorly. If you still have the gauge connected, it would be interesting to see how quickly pressure builds after the pump turns on. I would expect very quickly - a second or two.

After you get the engine started, what does the voltmeter show? The Bosch alternator does not start charging until you rev the engine past 1100 +/- 50 RPM (thermally balanced, whatever they mean by that. The FSM does not say whether this is alternator RPM or crank RPM, I believe it is the latter). On cold engine, mine does not run well until the alternator kicks in; symptoms similar to what you describe. On the first start of the day, I let the engine idle for a second or two, then I gently rev the engine until I see the voltmeter come alive; it does not take much. After that it runs fine.

Also, you replaced the cold start injector; but did you check the thermo-time switch that controls the cold start injector? This affects starting only, not running. I have had the thermo-time switch fail, and it made the car hard to start even on a not-so-cold morning. To check, unplug the electrical connector from the cold start injector, and get a set of probes to check the voltage across the two terminals of the harness plug. Make sure you make good, reliable contact, as there is no time for fidgeting when you do the test - the cold start injector fires for at most 8 seconds. Fewer seconds the warmer the Thermo-time switch is. Best to do this test first thing in the morning. Check the voltage as you crank the starter. Do you ever see battery voltage as you crank the starter?

The original thermo-time switch is no longer available. You might get lucky and find new old stock, or chance it and buy used. Bosch has a Classic program where they make replacement parts for some of these obsolete items. There is an electronic version of the TTS available under Bosch part number F026T03100. The original is a bi-metal thermo-switch with a resistive heating element. Just because in the 80's they did not want to do math inside the ECU...
 
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I saw this laundry list:

Intake Manifold
Spark Plugs
Distributor
Cap
Rotor
Fuel Filter
Fuel Injectors replaced with NOS injectors
Cold Start Valve replaced with NOS 124 Cold Start Valve
Electronic Control Module in the spare tire well
Thermo Time Switch
Electronic Ignition Control Module - in the well next to the coil - one of the rebuilds from Bob Brown(?) that have different internals.
Air Flow Meter - 3 different AFM's - 1 bought from here, 1 from a friend's spare parts pile, 1 borrowed from a properly running X1/9.
Double relay
Coil
Ballast resistor

Apologies if this has already been covered, but you've replaced every component except the one that affects FI drivability the most.......the coolant temp sensor.

DO NOT replace this until you've tested it. Follow this procedure to the letter.
 
The fuel pressure should stay high for some time; way more than seconds. Leaky injectors (main or cold start) will cause the pressure to drop, but you said you replaced all five. I think it is more likely to be the check valve in the fuel pump that is not working. But this would make the engine a bit slower to start, not cause it to run poorly.
Slow to start is one of the biggest pain in the arse problems I've been fighting since 2018. From what I understand, fuel pumps rarely fail, but if the check valve is failing, couldn't that explain the hard start problems I've been having?

If you still have the gauge connected, it would be interesting to see how quickly pressure builds after the pump turns on. I would expect very quickly - a second or two.
I'm pretty sure it did that - get the fuel pump to turn on (key on, push in the flap on the AFM) and the gauge almost instantly popped to 36psi and held there with the fuel pump was on.

After you get the engine started, what does the voltmeter show? The Bosch alternator does not start charging until you rev the engine past 1100 +/- 50 RPM (thermally balanced, whatever they mean by that. The FSM does not say whether this is alternator RPM or crank RPM, I believe it is the latter). On cold engine, mine does not run well until the alternator kicks in; symptoms similar to what you describe. On the first start of the day, I let the engine idle for a second or two, then I gently rev the engine until I see the voltmeter come alive; it does not take much. After that it runs fine.

I don't know that we've checked that, but we can. Like I said, getting the engine started is not just "turn key to the start position and let the starter crank for a second or two" although it was that way for about 18 years of owning the car.
Also, you replaced the cold start injector; but did you check the thermo-time switch that controls the cold start injector? This affects starting only, not running. I have had the thermo-time switch fail, and it made the car hard to start even on a not-so-cold morning. To check, unplug the electrical connector from the cold start injector, and get a set of probes to check the voltage across the two terminals of the harness plug. Make sure you make good, reliable contact, as there is no time for fidgeting when you do the test - the cold start injector fires for at most 8 seconds. Fewer seconds the warmer the Thermo-time switch is. Best to do this test first thing in the morning. Check the voltage as you crank the starter. Do you ever see battery voltage as you crank the starter?

The original thermo-time switch is no longer available. You might get lucky and find new old stock, or chance it and buy used. Bosch has a Classic program where they make replacement parts for some of these obsolete items. There is an electronic version of the TTS available under Bosch part number F026T03100. The original is a bi-metal thermo-switch with a resistive heating element. Just because in the 80's they did not want to do math inside the ECU...

I didn't test, but did replace the Thermo Time Switch 2 times - the first time thinking that was the problem (just realized my list is in reverse order - the ones on the bottom were replaced first) - that was probably one of the first. The 2nd time assuming the replacement might have been defective.
 
I saw this laundry list:

Intake Manifold
Spark Plugs
Distributor
Cap
Rotor
Fuel Filter
Fuel Injectors replaced with NOS injectors
Cold Start Valve replaced with NOS 124 Cold Start Valve
Electronic Control Module in the spare tire well
Thermo Time Switch
Electronic Ignition Control Module - in the well next to the coil - one of the rebuilds from Bob Brown(?) that have different internals.
Air Flow Meter - 3 different AFM's - 1 bought from here, 1 from a friend's spare parts pile, 1 borrowed from a properly running X1/9.
Double relay
Coil
Ballast resistor

Apologies if this has already been covered, but you've replaced every component except the one that affects FI drivability the most.......the coolant temp sensor.

DO NOT replace this until you've tested it. Follow this procedure to the letter.
I saw this laundry list:

Intake Manifold
Spark Plugs
Distributor
Cap
Rotor
Fuel Filter
Fuel Injectors replaced with NOS injectors
Cold Start Valve replaced with NOS 124 Cold Start Valve
Electronic Control Module in the spare tire well
Thermo Time Switch
Electronic Ignition Control Module - in the well next to the coil - one of the rebuilds from Bob Brown(?) that have different internals.
Air Flow Meter - 3 different AFM's - 1 bought from here, 1 from a friend's spare parts pile, 1 borrowed from a properly running X1/9.
Double relay
Coil
Ballast resistor

Apologies if this has already been covered, but you've replaced every component except the one that affects FI drivability the most.......the coolant temp sensor.

DO NOT replace this until you've tested it. Follow this procedure to the letter.

No problem or apologies needed. I appreciate any and all efforts at helping me figure out WTF is going on with my car.

That's already been replaced, but I called it the Thermo Time Switch. I might have used the incorrect name but the location as shown in the photo is the same.

Screen Shot 2021-09-14 at 11.28.31 AM.png


I've been replacing parts partly because I either had the spares, but mostly because up until now, I've been doing most of this work by myself. It's not always possible to crank the starter and check if the test light is on at the same time. I tried very long test leads but they didn't always stay on reliabily.
 
No problem or apologies needed. I appreciate any and all efforts at helping me figure out WTF is going on with my car.

That's already been replaced, but I called it the Thermo Time Switch. I might have used the incorrect name but the location as shown in the photo is the same.

View attachment 52094

I've been replacing parts partly because I either had the spares, but mostly because up until now, I've been doing most of this work by myself. It's not always possible to crank the starter and check if the test light is on at the same time. I tried very long test leads but they didn't always stay on reliabily.

The one your red arrow points to is NOT the coolant temperature sensor (CTS). The CTS (sometimes referred to as NTC 2 [negative temperature coefficient, because its resistance goes down as temp goes up], NTC 1 does air temp) is in the thermostat housing. But for testing purposes, it does not matter where it is, to test properly you test the circuit from the big plug on the FI control box.

BTW, the FI troubleshooter has mislabeled that figure, it should read Thermal Time Switch.

Here's another page from the FI troubleshooter that helps you figure out which is pin 13:
 
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The one your red arrow points to is NOT the coolant temperature sensor (CTS). The CTS (sometimes referred to as NTC 2 [negative temperature coefficient, because its resistance goes down as temp goes up], NTC 1 does air temp) is in the thermostat housing. But for testing purposes, it does not matter where it is, to test properly you test the circuit from the big plug on the FI control box.

BTW, the FI troubleshooter has mislabeled that figure, it should read Thermal Time Switch.

Here's another page from the FI troubleshooter that helps you figure out which is pin 13:
Gotcha. I'll add testing it to the list the next time I'm with the car - probably not till Wednesday or Thursday.
 
No problem or apologies needed. I appreciate any and all efforts at helping me figure out WTF is going on with my car.

That's already been replaced, but I called it the Thermo Time Switch. I might have used the incorrect name but the location as shown in the photo is the same.

View attachment 52094

I've been replacing parts partly because I either had the spares, but mostly because up until now, I've been doing most of this work by myself. It's not always possible to crank the starter and check if the test light is on at the same time. I tried very long test leads but they didn't always stay on reliabily.

I have a push button cable setup that you can connect to your starter and crank the engine by pushing the button. I use it all the time when needing to crank the car on my own while standing back at the engine bay. You're welcome to come by and borrow it...
 
I have a push button cable setup that you can connect to your starter and crank the engine by pushing the button. I use it all the time when needing to crank the car on my own while standing back at the engine bay. You're welcome to come by and borrow it...
Oooh.. sounds intriuging. I'll PM you about it....
 
Oooh.. sounds intriuging. I'll PM you about it....
If you put in a starter relay it is really easy to add a ‘starter’ button in the engine bay by adding two wires, one to line voltage and the other to the 85 terminal of the relay. I did this on the 850 to make it easy to do the valves and a few other activities. Just use a water proof momentary switch in the engine bay.
 
Oooh.. sounds intriuging. I'll PM you about it....
Hey Larry, I was a fiat mechanic for many years, I just thought I would throw some possibilities at you. First I would check for an air leak, there were 2 ways I would do this: once the car is running take a spray bottle with water in it and spray around the intake manifold, see if it affects the running, you can also do it ( carefully ) with a butane torch, again, spray it around the intake manifold and observe if the engine changes pitch/RPM's. Make sure your PCV is clear and functioning properly, have you checked the valve clearances ? I also had a situation where the ignition rotor failed, I see you have replaced it but you can check it by holding the coil wire over the rotor and cranking the engine, if it arcs to the top of the rotor then the rotor is no good ( shorting through the rotor ) Also, check the connector to the main computer and also the fuses, I had some that had green corrosion due to water ingress the would affect the running in really weird ways,
just a few things to check, hope this might help!
 
Hey Larry, I was a fiat mechanic for many years, I just thought I would throw some possibilities at you.
Thanks. I appreciate any suggestions....
First I would check for an air leak, there were 2 ways I would do this: once the car is running take a spray bottle with water in it and spray around the intake manifold, see if it affects the running,
Thanks. That was one of the 4th or 5th? things I checked.
you can also do it ( carefully ) with a butane torch, again, spray it around the intake manifold and observe if the engine changes pitch/RPM's. Make sure your PCV is clear and functioning properly, have you checked the valve clearances ?
Yes - the valve clearances were checked in the early stages of this weirdness.
I also had a situation where the ignition rotor failed, I see you have replaced it but you can check it by holding the coil wire over the rotor and cranking the engine, if it arcs to the top of the rotor then the rotor is no good ( shorting through the rotor )
Never had a rotor fail although when I pulled the distributor cap once, the center electrode spring was extended as if someone took it and gave it a good long yank.

Also, check the connector to the main computer and also the fuses, I had some that had green corrosion due to water ingress the would affect the running in really weird ways,
Thanks. Those were checked early on as well.
just a few things to check, hope this might help!
Thanks. I really appreciate the suggestions.....
 
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