Odd running (miss?)

[NEG]

Probably a daft question from me but have you checked the cam timing?

 

[kmead]

Sorry, from what you have written it is hard to tell what is happening. It seemed like you weren’t able to get it to start even using your advance the timing approach recently which suggested that your problems lay elsewhere.

I like Neg’s suggestion.

To run, the engine needs to be in time: fuel, compression and spark in the right order. You can’t get it to start at the normal timing, which suggests some of the above things are not happening in the right order or time.

Checking the engine as a system to verify the timing of the mechanical system is not a bad idea, like so many things it is getting the basics right. The mechanical timing of the intake of air, compression, power and exhaust is driven by cam and therefor the timing belt, check and verify this first. You can jack up the car, remove the right rear wheel, remove the needed covers and verify everything is in time and not replace everything. If it isn’t, a new timing belt is cheap and setting it all up again at square one would be a the right way to go forward as it will remove a whole set of variables. Once that is done, verifying the ignition timing is where it should be relative to the rest of the mechanical timing and you should be good assuming you have fuel.

The Wiki has an excellent timing belt installation section which I used to install mine last year after not touching one in thirty years.

To remove the connections from the injectors, you need to remove the locking wire using a pick. When it comes off it will likely want to fly so be prepared by holding the first end you pry out with a pair of pliers. Once the lock wire is off you can rock the connector left to right and walk it off the injector or pry it in the direction it will be coming off. Yes it is fussy and rather difficult in close quarters.

 

[Larry]

Sorry, from what you have written it is hard to tell what is happening. It seemed like you weren’t able to get it to start even using your advance the timing approach recently which suggested that your problems lay elsewhere.

I like Neg’s suggestion.

That's the first thing I did when all of this started. You take off the right rear wheel - I bump-timed the car. It's all good and the ignition timing is at 10 BTDC.

To run, the engine needs to be in time: fuel, compression and spark in the right order. You can’t get it to start at the normal timing, which suggests some of the above things are not happening in the right order or time.

Checking the engine as a system to verify the timing of the mechanical system is not a bad idea, like so many things it is getting the basics right. The mechanical timing of the intake of air, compression, power and exhaust is driven by cam and therefor the timing belt, check and verify this first. You can jack up the car, remove the right rear wheel, remove the needed covers and verify everything is in time and not replace everything. If it isn’t, a new timing belt is cheap and setting it all up again at square one would be a the right way to go forward as it will remove a whole set of variables. Once that is done, verifying the ignition timing is where it should be relative to the rest of the mechanical timing and you should be good assuming you have fuel.

Thanks for the explanation. It's almost a shame my timing belt is relatively new and I set the timing the first thing when all this started.

To remove the connections from the injectors, you need to remove the locking wire using a pick. When it comes off it will likely want to fly so be prepared by holding the first end you pry out with a pair of pliers. Once the lock wire is off you can rock the connector left to right and walk it off the injector or pry it in the direction it will be coming off. Yes it is fussy and rather difficult in close quarters.

Ugh... so it's as much of a pain as I thought.

 

[Larry]

Probably a daft question from me but have you checked the cam timing?

Yep. When all this started, I made sure everything was spiffy.

 

[kmead]

When it runs do you hear any loud noises from the cam pulley area?

I have read about the cam pulley wearing and allowing the cam to be out of time with the actual pulley meaning it allows the cam to be out of time with the rest of engine by the cam either ending up ahead or behind the timing of the rest of the engine.

This is usually portended by a loud noise at the cam pulley.

This has primarily been on 124 twin cams with phenolic cam wheels so it may not apply.

The killer about this problem is it will turn out to be an odd over looked area that none of us are seeing or thinking about.

 

[Larry]

When it runs do you hear any loud noises from the cam pulley area?

Nope. There are noises, but nothing loud from the cam area or in general. It sounds like it has for the past 19 years.

But in the interest of scientific evaluation since this is a decidedly strange problem, how would I verify this isn't an issue? Like I said, I'm open to almost any idea.

I have read about the cam pulley wearing and allowing the cam to be out of time with the actual pulley meaning it allows the cam to be out of time with the rest of engine by the cam either ending up ahead or behind the timing of the rest of the engine.

This is usually portended by a loud noise at the cam pulley.

This has primarily been on 124 twin cams with phenolic cam wheels so it may not apply.

The killer about this problem is it will turn out to be an odd over looked area that none of us are seeing or thinking about.

That's what I suspect given I've replaced nearly every component possible and every test I've done has yielded normal results.

Speaking of odd possibilities - could it be a voltage drop between the positive battery terminal and the starter? Or could it be the positive battery terminal? I've heard of that being the source of weird problems even if the cable looks good - as mine does.

 

[DanielForest]

Since you probably tried everything else...

Wild guess... Some of your symptoms may prove this is not the problem. But in my case, the timing belt tensionner was going bad. So after awhile (when the engine was getting hotter), the timing belt was also becoming hot because of the rough turning bearing , the timing belt was stretching and the timing was lost... Poor running engine, difficult to restart. Everything was back to normal when the engine was cold. Good luck!

 

[Larry]

Since you probably tried everything else...

Wild guess... Some of your symptoms may prove this is not the problem. But in my case, the timing belt tensionner was going bad. So after awhile (when the engine was getting hotter), the timing belt was also becoming hot because of the rough turning bearing , the timing belt was stretching and the timing was lost... Poor running engine, difficult to restart. Everything was back to normal when the engine was cold. Good luck!

Wild guesses definitely appreciated, but the engine also doesn't want to start when it's stone cold (after a 50 hour rest or almost 2 weeks) as well as when it's been heat-soaked for 45 or so minutes after being brought to operating temperature. After it's been run to operating temp and continues to be run or idle for a bit, it will still start after about 10 or so of sitting. Also, the engine runs fine when it's warming up and fully warmed up.

The odd miss I was experiencing before this weird no-start issue was only at certain RPMS and with a relatively gentle acceleration. A hard acceleration would never exhibit the problem.

 

[NEG]

Sorry to keep on about this but I would double check the camshaft timing is correct on cylinder 4 and maybe perform a compression check as well.

 

[Larry]

Sorry to keep on about this but I would double check the camshaft timing is correct on cylinder 4 and maybe perform a compression check as well.

It's okay, but it's been double and triple-checked and by other people than just me. This started when trying to debug another problem when the car would start properly but had an issue while driving.

 

[Larry]

Another update and a possible source of my woes??

Cliff notes version... a previous mechanic or owner also ran a wire for the headlight relay to the positive side of the battery. Except (from what I can tell) the wire he used was too short, so he put in a different battery that has the positive terminal on the passenger side facing into the front trunk. And since the wire used was too short, the positive battery terminal connector was positioned at an angle so the top would clear this headlight relay wire. Which meant the leads powering the car coming off the positive battery terminal were bent next to the terminal for years. I'm including a photo of what the connection looks like. The yellow wire going off to the left runs to a fusible link for the amp located in the front trunk. The yellow wire going down to the bottom of the photo runs to the headlight relay. The black wire at the bottom of the photo is for the battery tender.

Over the weekend, I did some minor items and repositioned the battery cable so the lead was straight instead of being bent. I also disconnected the wire for the headlight relay (more on that in a bit). I decided to see if the car would magically start - not expecting it too since it's been sitting for a few weeks and it hasn't any other time it's been stone cold.

And... it started. Almost like it used to all the time before this mystery no-start problem started. I was shocked to say the least. It stalled, but I was able to restart it and let it rev for a bit. That wire for the headlight relay I disconnected apparently also controls the dashboard instruments as none of them worked. I let the car idle for about 5 minutes and then shut it off since I didn't have a working temperature gauge. I reconnected the disconnected wire for the headlight relay but in the process, manipulated the positive battery cable and the car wouldn't start, but I got my dashboard instruments back.

This sort of tells me the fault lies in the positive battery terminal connection. It's got enough of a connection to turn the starter motor but it can't carry the full load so the car won't start(?) Looking for advice on replacing the positive battery terminal.

And has anyone else ever experienced something like this?

Larry

 

[kmead]

Yes the battery should have the positive terminal near the firewall and be toward the center of the car. The negative terminal should be next to the firewall and near the outside of the car.

I would redo all those connections to go to a terminal block that has only one connection to the battery. Those crimps on the wires look decidedly suspect. You might also consider getting a new positive connector as that one has certainly seen better days.

I was able to get a suitable battery at Costco which has worked well on my car for many years.

 

[Larry]

Yes the battery should have the positive terminal near the firewall and be toward the center of the car. The negative terminal should be next to the firewall and near the outside of the car.

I would redo all those connections to go to a terminal block that has only one connection to the battery. Those crimps on the wires look decidedly suspect. You might also consider getting a new positive connector as that one has certainly seen better days.

I was able to get a suitable battery at Costco which has worked well on my car for many years.

Thanks....

That's what I thought. The mechanic who did this was known for doing some interesting repairs - some seem elegant, others somewhat less so, like this bit with the too short wire to the battery or the fact he tied the headlight relay to the dashboard gauges. He seemed to love using crimp connectors to extend wires - I can only assume he didn't do that here since it wouldn't have looked "nice."

For replacing the connections to a terminal block, I saw the Headlight Wiki but is there any additional writeup or something with pictures that explains it a bit more? Given the other surprises I've found with the car, I'm hesitant to start diving into the fuse panel out of concern for what else has been done in there - like how he tied the yellow wire that runs from the battery to the relay to the dashboard gauges. That makes me think he just took any fuse without regard to what he was doing?

I was thinking I should replace the positive battery connection too. I suspect it's not just a matter of cutting and re-crimping - that seems far too simple. Is there a recommend way to replace the positive connector?

Great advice about Costco. I've been buying all of my car batteries at Costco for years. My X currently has a Walmart battery because Costco stopped selling a battery for this particular setup for a bit.

 

[Larry]

Long overdue update....

And the car still won't start but now we're spending some dedicated time looking at it and it's not just me - deer in the headlights look.

Same problem as before - car will crank, but needs the gas pedal depressed a bit here and there to get it to occasionally catch and start, which is not the way a FI engine should - turn the key, let the engine crank a couple of times and it should fire right up.

One idea we're going to pursue is low fuel pressure which would pretty much explain almost all the hard starting problems I've been experiencing with the car. We'd also like to be able to get an idea of what the Lambda sensor is seeing. Is there anyway to do this?

 

[kmead]

The lambda sensor on these is pretty stupid, meaning it really doesn’t do much. The ECU is getting a signal of when it is at the correct mixture and is constantly edging up to the correct mixture, overshooting and falling back to do the same over and over. I don’t know what you are hoping for from this part of the system. Sort of like Marco Polo or the whole warmer cooler game.

Have you verified the AFM flap is opening? A warped/sticking flap could produce the problem you are describing, it should move smoothly and effectively silently with only spring pressure and no scraping.

Does the fuel pump run when you have the key in the ‘on’ position and you move the flap? Have you verified flow through the fuel rail by running the fuel pump and disconnecting the return line to dump into a bucket? A fuel pressure gauge can be plumbed into the system if you really think that is the problem.

Is the cold start injector actually firing? It could be the opposite of what you are thinking, it could be that the cold intake is too lean to start a cold engine thus why you are putting the gas pedal down to get enough fuel into the engine to fire. Have you run through the diagnostics to verify that subsystem in its entirety is working?

Yes I am grasping at straws here.

 

[ng_randolph]

We'd also like to be able to get an idea of what the Lambda sensor is seeing. Is there anyway to do this?

The output from the lambda sensor isn't going to help you much when diagnosing starting problems. Until it is warmed up by the exhaust, the lambda sensor does not provide useful output.

 

[Larry]

The lambda sensor on these is pretty stupid, meaning it really doesn’t do much. The ECU is getting a signal of when it is at the correct mixture and is constantly edging up to the correct mixture, overshooting and falling back to do the same over and over. I don’t know what you are hoping for from this part of the system. Sort of like Marco Polo or the whole warmer cooler game.

Just trying to examine anything else that might be the cause of the problem. Every part that can be replaced has been and the problem persists.

Have you verified the AFM flap is opening? A warped/sticking flap could produce the problem you are describing, it should move smoothly and effectively silently with only spring pressure and no scraping.

Yep. Verified and also the problem has happened with 3 different AFM's. 1 bought from here, 1 from a friend's spare parts pile, 1 borrowed from a properly running X1/9.

Does the fuel pump run when you have the key in the ‘on’ position and you move the flap?

Yep.

Have you verified flow through the fuel rail by running the fuel pump and disconnecting the return line to dump into a bucket?

We have not done that yet, but after cranking for several minutes - 10 seconds on, rest, 10 seconds on again, things start to smell somewhat rich.

A fuel pressure gauge can be plumbed into the system if you really think that is the problem.

No idea if this is the problem, but it's an area that hasn't really been extensively explored.

Is the cold start injector actually firing? It could be the opposite of what you are thinking, it could be that the cold intake is too lean to start a cold engine thus why you are putting the gas pedal down to get enough fuel into the engine to fire.

Yep. It's also continued to do this with a NOS 124 Cold Start Valve.

Have you run through the diagnostics to verify that subsystem in its entirety is working?

Almost everything. The problem has persisted even when replacement parts are swapped in - one at a time - swap a part, does the problem persist? Test drive, try the next part. I can see a few replacement parts having the same problem, but *every* part?

What parts? Here's the list in the approximate order they were replaced:

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

Yes I am grasping at straws here.

As we are too... but there has to be a solution to this....

 

[Larry]

The output from the lambda sensor isn't going to help you much when diagnosing starting problems. Until it is warmed up by the exhaust, the lambda sensor does not provide useful output.

Thanks. We're grasping at straws and that seemed like a viable straw...

 

[Larry]

We got the car started, but it was a bitch to start - as it had been before. Spraying starter fluid into the intake didn't make much of a difference.

As others have suggested, we're beginning to suspect the Fuel Pressure regulator and fuel pump. I've pull the vacuum hose off the regulator and give it a whiff, but there's no fuel smell.

Is it possible to rebuild one? MWB doesn't stock it, but Fiatplus has used ones. But if a used one is about the same age as the one in my car, is there anyway to tell if it's good?

 

[ng_randolph]

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.

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 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.