Stock 1986 L98 coupe.
Last Friday I was trapped in traffic behind an accident for about an hour. Temp got up to about 230 or so and would cool back down with the fan kicking in. Got home, no problem. Saturday started the car and it would not keep running. Spitting and backfiring. Yesterday it acted better at first and then, once away from home, it came back with a vengeance. It threw the first code in over a year. Code 32 for the EGR - found a disconnected vacuum line at right rear of intake, put back in place and code is gone. Noticed brake fluid leaking at master cylinder/ booster connection - could this create a substantial vacuum leak at this site? Replaced the plugs and put in 160 thermostat. A little better if you put your foot in it. Fuel pressure is 44 with igniton on, 40 with engine running and drops to 10 within 3 seconds of shutting car off. I know that I need injectors, but can they cause the cat to clog up and effect the performance this badly? Oh yeah, very loud metal rattle heard out right side once car gets hot as of yesterday, sounds like rusted out muffler (cat back exhaust is two years old). It ran this way when I bought it and didn't straighten out until I replaced the ECM. Don't want to do that on a hunch yet, though. All this trouble seems to relate back to my long wait on I95. Any ideas?

Thanks in advance,
Scott

 

Lets take this apart and make some sense out of these problems.

1) The EGR code - yes. anytime a vacuum line is leaking, drivability becomes a problem.

2) The injectors are possibly the problem, but also check the fuel pressure regulator. Remove the vacuum tap from the regulator and see if fuel comes out. If so, replace ASAP.

3) Overly rich conditions will kill a cat. The raw fuel will hit the hot substrate causing all sorts of bad things to happen. More then likley, the rattle is a dead or dying precat. And when a cat clogs? All bets are off. I would suggest dropping the exhaust system and removing the pre-cats. Before they destroy your main cat.

The wait on I95 only added to the problems, but didn't cause them. You have other mechanical problems that were made worse by the wait.

You really need to get a copy of the helm manual for your year, www.helminc.com.

Good luck.

 

Already have the Helm - that's how I got this far. EGR is fine now. attle doesn't happen until engine temp is greater than 200, and then sounds like an entire tribe of Pygmies beating frying pans on washtubs under there. Getting ready to crawl under and check. 3 plugs were soaked with gas when I changed them last night, and leaking injectors have been going on for over a year - that's why I'm worried about the cat (seems like the O2 sensor would throw a rich code if fuel was that strong in the exhaust). You didn't address the vacuum leak at the brake booster. Sorry if that is a dumb question - there's cook books in the house, but you don't want me to bake you a cake, either.
I'm going to chek the FPR now and check back here in a little bit. Thanks again.

 

the brake fluid indicates a failing master cylinder. The downside? fluid can enter into the booster and harm it.

I would be worried about the cats, too. But the precats would take the brunt of any injector failure.

I would loose the precats and update the main cat to a highflow unit.

 

FPR has no gas in the line, good vacuum. Al vac lines check out between 10 - 12 at idle, increase of 5 with throttle. EGR function seems appropriate, unsure if stuck open from buildup, though (chart 7 missing from my Helm manual).
At this point, I think I will have t bite the bullet and replace injectors and follow your suggestions about the cats. Then I will replace ECM, if needed. Any suggestions as to high flow main cat for a 1986 stock? Thanks for helping me work through this one.
Scott

 

check with Carsound (part of Magnaflow) or Random Technologies. RT are available via Exotic Muscle.