Testarossa ECU disconnect - running hot

I have a 1990 Testarossa (US). I had a major service performed two years and about 3000 miles ago. At that time all injectors were replaced, as were the distirbutor caps, plugs, and cables. In addition, the cylinder heads were removed to remove carbon buildup and new valve guides were installed. New cylinder head bolts were used when replacing the heads.

The car was running great until just a few weeks ago when the connection to the ECU failed. This prevented the car from starting. Took it in to my mechanic who found the problem and reconnected the ECU. As I drove the car home, I noticed that when I had to stop the car, the idle RPMs would drop to about 600, the engine light would come on, it sounded like the engine had stopped, but if I feathered the gas it would come back on. This happened several times and eventually I kept the RPMs about 1500-2000 when I came to stops. I thought maybe this was due to the ECU needing to "recalibrate" by getting some miles on it after the re-connection. I've driven it about 100-150 miles since, but a lot of it has been around town or local highways. I've been reluctant to drive it any great distance from home since it still isn't running correctly. I still get the symptoms mentioned above, and at times it seems like it starts chugging in 1st gear (as though not all cylinders are firing or some aren't get enough gas.

Shortly after this happened, I was looking around the car and noticed the black part of the bumper above the driver side exhaust was damaged - as if it got too hot. I also noticed that the residue on the driver side exhaust was more whitish as opposed to the more normal black residue. Also, the Tubi exhaust system looks discolored at various points. I've attached a picture if this helps clarify my comments.

My mechanic is looking into the matter. I've tried looking in this forum for similar problems. I've seen some things that look similar but I'm not sure they're the same thing.

These were some of the things I've found or were thinking about. From what I've gathered it looks like there might be unburned fuel going to the cats which cause them to overheat. Note that the exhaust temperature overheat lights ('slow down 1-6") did not come on.

1. Perhaps the plugs got fouled during the ECU disconnect issue. This is a rather simple thing to check.

2. I found a thread about "multipin plugs on the coil pack" causing a problem for one owner. My mechanic had pulled the cable from the coil and verified that both were firing when the engine was running (they were). But again, maybe there is an issue when the engine isn't running correctly under certain conditions. I don't know where the "mujltipin" connections on the coil pack are, but I'm sure my mechanic does.

3. Swap the ECUs and see if the condition follows the ECU. This sounded like an easy thing to do, but I don't really want to deform the bumper on the other side of the car, too. Seems like a smog testing machine might be able to provide a lot more information of what is coming out of the exhaust. Perhaps the temperature, too. FWIW I had to have the car smogged in March and it passed without any problems.

4. Perhaps the MAF unit is faulty? I'm not sure what MAF stands for, but again if it is something to check, my mechanic can do so.

Has anyone encountered a similar problem? Or some other possible things to check? I'd like to get back to driving the car, but am a bit leery until this gets resolved.

If more information is needed, please let me know. The car is in the shop right now, so if information is needed from the car it will take a bit more time than if it were in my garage.

Thanks in advance for any and all help.
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Found this thread today. My car seems to exhibit many of the same symptoms. There are many suggestions in the thread that I will check out.


http://www.ferrarichat.com/forum/boxers-tr-m/553016-help-please-car-dying-stops-after-major.html

 

Found both pressure regulators were leaking. Here is a thread on the issue:

http://www.ferrarichat.com/forum/boxers-tr-m/417425-ke-control.html

Since these are no longer available, the solution is to contact

CIS Flowtech - Rebuilding Bosch Fuel Distributors & Warm-Up Regulators

Will post if there are any additional changes required.

 

First let me apologize for not using the correct terms for these parts. I know how important it is for communication and resolving problems. I'll redouble me efforts to be more precise.

One of the fuel pumps was replaced about 8000 miles ago (2013). Both fuel pumps are functioning properly. There was plenty of gas getting to the EHA, which were indeed leaking. Although I hadn't put a lot of miles on the car since this first started, it did make me concerned about a possible fire.

The original EHAs are on their way to Larry to recalibrate. Sounds like this might take a few weeks to get back. But at least I'll have a car I can drive safely.

Although the "Slow down" lights did not ever come on, I'm wondering if this condition may have damaged the catalytic converters. I just had the car smogged a couple months ago (before this started), so I'm sure I'll find out the next time it gets smogged (2 years) whether there was any damage to the cats. I put probably less than 100 miles on the car while it was in this state, so I would think they would be OK. I know I could take it to a smog station at any time, but am a bit concerned of what they might force me to do if it fails. If the cats are bad, although the car may be producing more pollution, would there be any serious problems that might occur if I run it in this condition? Or is it better to get it fixed / checked ASAP?

And thank you bpu699 for mentioning the laser thermometer. I hadn't even thought of it, but I'm going to get one right now!

Thanks also to Steve and turbo-joe for also replying and assisting me with this issue and clarifying some of my previous posts. It is very much appreciated.

Once I get the EHAs back and installed I will update this thread to let everyone know how this worked out. ETA is mid-July.

Thanks everyone!

 

I had replaced the stock exhaust with a Tubi exhaust about 4000 miles ago (during the last major service). There is a bit of discoloration at the tips as well as some of the tubing before the cats.

After you explained the possible problems with the heat and condition of the cats, and I just step back and remove the emotion from my thinking, I believe you're right. Better to check them and ensure they are OK vice hoping for the best and perhaps losing the entire car to a fire. The old "ounce of prevention is worth a pound of cure". Since the EHAs will take several weeks, I can check and repair / replace the cats (if necessary) while I'm waiting.

Thanks for pointing out some of the serious problems that could arise from not checking the cats.

 

Sorry about the delay in the update. The parts did not come in until mid-September. The new parts were installed.My mechanic found a mis-fire in one of the cylinders and replace all the spark plug connects with the newer version. Things run great at idle, but once at revs above idle, the mixture goes full rich. He believes the new parts weren't calibrated correctly so will be taking them off and testing them. So although there is an update, I'm not sure there was much to add. Once we track down this issue I will provide another update.