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Engine stalls and runs rough. Timing chain?


fun car guy

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OK, here are all the "E" codes:  E178 pwr steering, E174 park-neut, E171 Brake, E182 4th gear, E180 3rd gear, E179 2nd gear, there were no "H" codes.  Not sure I did this right, I hope this helps.

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ECM codes should look like E0xx. The two digits on the end are the code you are looking for in the chart below. The numbers you posted don't seem to be correct. Try again. You can't hurt anything by checking the codes.

 

ecm_codes.jpg

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By the way... ODB2 codes you will find on the internet don't apply to your Reatta. This is a OBD1 diagnostic system.

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I went through the process three times with the same result, apparently I'm missing a step.  Thanks, will try again tomorrow now that i know exactly what I'm looking for.

The engine starts quickly, no backfire or anything, just shudders.  

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It has been a while since I looked at mine but I believe history and current are actually spelled out below the code on the CRTs.

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For ensuring the spark plug wiring is correct here is the diagram. 

 

I was thinking if not the MAF it could be a faulty Idle Air Control valve maybe? I think that would only cause the problem at idle though.

Screenshot_2021-02-07-17-26-34.png

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fun car guy

On the same subject, in going through the repair receipts given to me by the previous owner(s), I found one from a Buick dealer to replace a leaking water pump at 127,000 but nothing about the timing chain.  It seems odd that, at this mileage, the mechanic wouldn't do the job right and also replace the chain, sprockets and tensioner!  Any thoughts?

 

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DAVES89

I went about 265,000 miles on the original timing chain in the Red, 190,000 on the Black and 130,000 on the 'vert [did the 'vert only because it is going to Brownville for the rest of my ownership of it and my mechanic buddy isn't coming along]. The Black that 2 seater got from me still has the original timing chain at 215,000 miles [the car has 100,000 more as it had an engine/tranny swap].

These are 300,000 mile motors before any engine work needs to be done.

I think you are looking for a big problem when your issue is a much smaller one.

Edited by DAVES89
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Ronnie
1 hour ago, fun car guy said:

It seems odd that, at this mileage, the mechanic wouldn't do the job right and also replace the chain, sprockets and tensioner!  Any thoughts?

Keep in mind that the 3800 engine has a timing chain - not a belt that needs to be changed as part of routine maintenance like most newer engines have. The chain and gears are intended to last the life of the engine as Dave said.  Changing the water pump is a relatively simple job that only requires draining the coolant and removing a few bolts. Replacing the timing chain is still a pretty big job, even when you have the water pump off, that isn't justified unless you suspect a problem with the timing chain or the engine has extremely high mileage.

 

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2seater

Perhaps there are memories of the old days when GM and perhaps others used a synthetic or synthetic coated timing sprocket which did break down and chip off. The 3800 has an all steel timing set with a tensioner. The photo is of a workup on a junkyard project engine but is the typical setup. In this case it is using the original (old) style tensioner. The only thing the chain drives is the camshaft and the balance shaft. There is no load from an oil pump as that is crank driven. This is also a non-interference engine as well.

DSC01135.JPG

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fun car guy

Well, after listening to the engine for a while, it seems there's still something not right.  I tried feeling around between the engine and firewall to trace the plug wires to their corresponding plugs but for the life of me, I can't get them loose!  Maybe it's easier from underneath but I don't have hoist and I HATE working underneath a car!  Anyway, I think the suggestion of switched wires is a possibility but can't imagine the owner accepting the car as it's running now.  It starts, doesn't stall but runs rough, smooths out a little if I give it some gas but still not right butthe CRT screen says there are no malfunctions!  BTW, I see a round, green sticker on the back of the rear view mirror that says "Green Team", what's that about?

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Philbo

I think when it comes to troubleshooting rough idle/running you have to start by eliminating simple causes and progress to the more complicated ones. This is how I break it down when I am troubleshooting an issue.  

 

First, for an engine to run 4 things are needed:

1. Fuel.

2. Air

3. Spark

4. Compression

 These areas are where you focus, although I would leave 4 for last unless you have reason to believe that there is a compression issue.

 

I usually start with spark. So things I would check in relative order of complexity are:

Spark plug wires connected properly?

Are the terminals at the coils or plugs corroded?

Any signs of deterioration of the wire insulation?

Does the car run differently in dry vs wet conditions?

Get a spark plug tester and test that each plug is getting spark. Keep in mind that having a spark doesn't mean that the spark is as strong as it needs to be.

Remove the plugs and check for fouling or incorrect gap (should be .060).

You could eliminate all these by just going ahead and replacing the plugs and wires. Do make sure to check the gap even if the store says they are 0.060 I bought new plugs and they were all at 0.045 even though advertised as 0.060.

 

If it is not any of these it could be the coils, I don't really know the best way to troubleshoot coils other than replace so I would come back to coils after checking some basic things from the air and fuel categories.

 

I will post on those here in a bit

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Philbo

First, for an engine to run 4 things are needed:

1. Fuel.

2. Air

3. Spark

4. Compression

 

Now on to number 2, air. Usually the problem is the engine measuring the wrong amount of air, which could be a sensor (others mentioned the MAF) or it could be due to a vacuum leak, which may not cause an engine code.  I would check the following:

Check air filter for clogging

Visually inspect the vacuum lines, particularly those connected to the throttle body, valve cover(front of engine) and PCV valve(near the power steering pump I think?).  Look for any vacuum lines that are disconnected or damaged. Wiggle them and see if that effects the rough running.

Check to see if the intake manifold or valve covers show signs of significant oil leakage. If you have a bad enough leak in these gaskets it could cause vacuum problems. (slight oil leaking doesn't mean you have a vacuum problem)

 

Let me diverge and talk about the positive crankcase Vacuum (PCV) system for a sec (disclaimer i am not an expert, just my basic understanding of it). The PCV system uses engine vacuum to pull a steady vacuum on the crankcase. This is to capture very very small bits of unburned hydrocarbons that inevitably slip past the piston rings during compression and bring them back through the intake to be reused rather than building up in the crankcase. If you have a bad PCV valve or a bad enough vacuum leak somewhere either in the hoses or gaskets, it will pull air into the intake that has not been measured by the MAF.  If bad enough this can cause poor running.  Another indication that you have a bad PCV leak is if you pull the intake hose off the throttle body and see that the throttle body is very oily. It may be dirty but shouldn't be oily. What happens is if everything is sealed up properly there is very little actual air flow. But if you have a leak, now you have air flow from that leak. If it is bad enough, it will drag oil mist from the crankcase up into the intake.

 

The other thing to check is the idle air control valve (IAC). this regulates the flow of air at idle to ensure proper RPM and smooth running.  If it smooths out when you press the gas it could be a bad IAC.

 

One other thing to mention is that it is entirely possible that a rough running problem is a combination of things. Maybe you need new plugs and wires AND need to clean the MAF sensor for example. This is just kind of my general methodology of what to check.

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Philbo

Ok last one for me is fuel.  This is an area that I have less experience with mostly because none of the cars I have owned have ever really had a problem with fuel delivery (knock on wood lol). Here is however the approach I would take.

 

First eliminate the possibility that there is water in the fuel tank and dump a bottle of dry gas in it. 

Then I would dump a can of something like seafoam or any other of the dozens of fuel system cleaners out there in there to see if that makes any difference.

Then I would check the fuel pressure. You can usually borrow a fuel pressure gauge at your local parts store. If the pressure is good then it is unlikely to be fuel related. If the pressure is bad it could be a clogged fuel filter, a problem with the fuel pressure regulator, or the fuel pump going bad.

 

It is also possible that you have a bad fuel injector, but I feel like this would be less likely.

 

Only after eliminating all of these things would I suspect something like timing chain or a problem with compression in one of the cylinders or something.  Others may have other ideas of simple stuff you could check as well.  This would be my approach to troubleshooting rough running. In my experience on my own vehicles usually it has been spark/ignition related and often simple like a bad wire.

Edited by Philbo
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2seater
1 hour ago, fun car guy said:

Well, after listening to the engine for a while, it seems there's still something not right.  I tried feeling around between the engine and firewall to trace the plug wires to their corresponding plugs but for the life of me, I can't get them loose!  Maybe it's easier from underneath but I don't have hoist and I HATE working underneath a car!  Anyway, I think the suggestion of switched wires is a possibility but can't imagine the owner accepting the car as it's running now.  It starts, doesn't stall but runs rough, smooths out a little if I give it some gas but still not right butthe CRT screen says there are no malfunctions!  BTW, I see a round, green sticker on the back of the rear view mirror that says "Green Team", what's that about?

The car does a pretty good self diagnosis but it doesn't do spark; so crank sensor, coil pack, ignition module, spark plugs, spark plug cables are all subject to manual intervention on the owners part🙄 It doesn't do fuel either except via inference from the O2 sensor and the adjustments it makes to maintain the target fuel mixture. Those rear spark plug wires with the stock metal boot covers and big harness in the way are a stinker and I have known people to leave them alone while the others were serviced? Maybe someone that has done this regularly can give a tip on what works best.

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Philbo

Yeah they are a bit of a tight fit.  I found it easies to get to them by climbing up over the engine with my knees on the cross-member that runs over the radiator and reaching down. Not the most comfortable position though.  For routing the ones to the back, i had to rout the coil end from the back and it was a tight squeeze. The old ones do get kind of stuck on there. You just have to work them and they'll eventually come free in my experience. Just watch your knuckles when they do. 

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fun car guy

Condensation in the tank is a possibility as the car sat out in the weather for some time.  Also, the tank, sending unit, and gas lines were replaced at 142,089 miles and the injectors replaced at 8/2018.  So, I still feel spark is the problem and quite likely the leads are switched. I also feel just replacing the plugs and wires couldn't hurt, I just wish it were easier to check that out!

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Ronnie
15 minutes ago, fun car guy said:

So, I still feel spark is the problem and quite likely the leads are switched.

The wires being stuck on tightly is a good sign that they haven't been removed for a long time. Perhaps the plugs in the back weren't changed at all and they need to be.

 

If you think the wires being crossed is causing the problem you could trace the wires back to the coil to verify without pulling off the spark plug wires. If you find that they are wired wrong you could just swap the wires on the coils to see if the engine runs better.

 

I put new plugs in my car when I first got it about 13 years ago. To get more clearance in the rear I removed one bolt from the dog bone and pulled it up, then used a long pry bar to pull the engine forward and I held it in place with a tie down strap from my boat trailer. I still had to lay on a piece of cardboard on the engine but it gave me a little more room for my big hands to get the wires off and remove the plugs.

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fun car guy

Okay, following your instructions, it asked if I wanted the ECM and it simply said there were no codes.  Then, as I said yes to each, it gave the following  ED codes:  ED01 TPS, ED4, coolant TP, ED07OX. sensor, ED08 Deg spark, ED10 Batt volts, ED11 RPM, ED12 gave the word "nothing", ED16 spark angle, ED17 old PA3, ED18 cross CTS, ED19 Int fuel, ED20 BLM fuel, ED21 Air flow, ED22 one AC, ED23 MAT, E98 IGN cycles and ED99 Prom ID.

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