[KingLuke663]

I was on my way home last night from a friends at about 2am, while driving on the freeway I was coming up on my exit and started to ease up on the gas pedal. All of a sudden I feel the car basically start slowing down, a lot, so I try to accelerate and it’s not. I put it to the floor and basically it stayed at 40mph. I threw my hazards on and kept going because I was less than a 2 minute drive from my home. I luckily had green lights at both the exit and the next light, so I never had to stop fully, but I had to slow down for a corner that lead up a small hill. I went maybe 20mph around the corner and when I started going up the small hill the car was coming to almost a stop. I randomly tried to lift the gas and push it back down, basically pumping it, and it was able to get me a little acceleration and up the hill. I was able to park it at home.

There was no trouble lights that came on, not even a check engine. What could this be? I turned the car off, and then back on and it struggled to start and rough idled, so I turned it back off. I popped the hood and checked the transmission fluid and it was fine, not dirty and not empty. Does anyone have any idea how to diagnose this and what it could be??

 

[Tripwire]

moved to Eldorado forum for better visibility - identical thread deleted - one post per issue please

 

[dogbiscuit]

First check for codes then check fuel pressure AND volume, then check ignition timing, if it is off either the timing chain is bad or the distributor drive gear is going. You might want to change the fuel filter and check the old 1 for water

 

[scottelderado]

Hi Luke, first guess is TCC solenoid (torque converter clutch solenoid). I had the same symptoms when slowing from highway speed, near stall. Search the forum for my posts about it.

 

[scottelderado]

As a temporary workaround, you can manually shift gears. There is a code for a failing TCC; check the codes anyway despite no trouble lights.

 

[dogbiscuit]

Usually the converter will unlock after shifting to neutral or turning the car off and shouldn't affect starting, my $ is on the timing chain

 

[scottelderado]

Your money may win, DB. But as I recall I had trouble starting right after TCC problem. But memory fuzzy.

 

[dogbiscuit]

you could be right as well Scott, it is hard to say with the limited info we have. I don't think the converter staying locked would affect acceleration on the highway though. Keep us posted KingLuke663 on what you find

 

[KingLuke663]

I just tried to start it to see if I’d be able to drive to work with it today, but when I started it the idle was super rough. I tried just reversing and it was struggling with even that, so I pulled back in and shut it off. The entire car was shaking pretty rough and didn’t sound too hot. It felt like it was gonna stall just going into drive. I have to walk to work right now so I’ll run codes tonight

 

[scottelderado]

That sucks. Doesn’t sound like a bad TCC anymore.

 

[dogbiscuit]

maybe you will luck out and find plug wires disconnected or something easy to fix. Fingers crossed for you

 

[DB2Guy]

Rough idle and lack of acceleration ability sounds like a fuel supply issue to me. Likely the fuel pump or fuel filter needs to be changed. A clogged catalytic converter could possibly cause the same symptons. TCC would throw a service soon code and light up the dash light.

 

[1979 Eldorado]

If the OP hadn't mentioned it running poorly after I had a failure of a 1984 Toronado which was very similar to what was described. Mine failed suddenly at highway speed. I could tell that if it slowed it couldn't recover speed. When mine failed it just felt like no matter how much accelerator I gave it I could, at best maintain speed, as if the transmission was massively slipping. I made it to a friends driveway which was very close. I immediately assumed the transmission went bad. I "knew" that's what it was at the time and a shop ended-up changing the transmission and the converter. I later wondered if it could have been only internal converter failure. Once I came to a stop I recall it wouldn't move in any gear. It ran as normal. That was a very long time ago but considering they are both the same year and both E-Body I'll be interested to hear if you find the root cause.

Scott

 

[KingLuke663]

I’m still at work but I while talking to coworkers, the idea of it being a fuel issue isn’t crazy. I bought this car from a friend over a year ago, and the car had been sitting for awhile. While talking to people today I realized that I don’t recall ever changing the fuel filter, which sounds ridiculous when I think about it, but I’m hoping that it’s just something like that causing this. I’ll update when I get home and run codes.

 

[dogbiscuit]

The idea of the cat plugging is possible if the substrate has started to break up and is now completely blocking the exhaust pipe, you would think it would run ok for a bit until back pressure built up though. you can bang on the cat with your fist and you will hear the internal rattle if this is happening. Remember the car was running fine so start with the basics (post # 3) It very well could be a fuel issue

 

[smokuspollutus]

I would say it is something mechanical inside the engine.

My immediate thought is the timing chain jumped a tooth. Letting off the gas suddenly unloads the chain and if the chain/gearset is original, it’s more than likely the chain is stretched and the gear is missing a few teeth. How many miles are on the car?

 

[dogbiscuit]

Did they use that nylon cam gear in the 4100? Is the 4100 an interference engine? if so you don't want to try and start it until checking base timing as it may cause damage to the valves that may not have occured yet

 

[smokuspollutus]

Yes, if original it will be the nylon one. Last year I replaced one of mine, 100k miles and 40 years and go figure, it was perfect. But I also have had them fall apart with way less age and miles.

Good news is it is not an interference engine.

 

[KingLuke663]

I would say it is something mechanical inside the engine.

My immediate thought is the timing chain jumped a tooth. Letting off the gas suddenly unloads the chain and if the chain/gearset is original, it’s more than likely the chain is stretched and the gear is missing a few teeth. How many miles are on the car?

Just under 76k on the original engine

 

[KingLuke663]

I went to run the codes and none popped up, just was at .7.0 I then tried to run a switch test and nothing went wrong. So then I put it in .9.0 to try and run the engine check but it wouldn’t advance, I would press the instant/average button and it wouldn’t change. I didn’t have the engine on though, so that might’ve been it. I was thinking about trying to run the spark test through it but it had requirements like having the engine on and warm, and I’m worried about having the car running in case it damages anything further.