92 Eldorado loss of power, missing after new intake gaskets

[Gossamer63]

Hi all,

First time posting and looked around but not able to find anything in here so here it goes:

My son and I replaced the intake manifold gaskets, (previous owner used wrong set) and since getting it back together it sounds like it is missing and and very little power. Push the pedal to the floor and almost nothing. Also runs rough like it is missing in gear but very smooth when in park. Checked all vac lines, double checked the firing order, and so on. I don't think the timing was set properly by the nut jobs that worked on it before (could start a thread on what they did) it seems to be firing on the leading edge of the cap. New plugs, wires and rotor. Do I need to look at the timing or is something else going on.

Thanks in advance.

[Cadillac Jim]

I believe that you can read out the OBD codes with a 1992 model, and that is where you should start, particularly if the Check Engine light is on. If it has a vacuum leak there should be a code.

Poor throttle response can be due to a clogged catalytic converter or muffler, poor spark timing, spark plug wires to the wrong plugs, clogged air cleaner, etc. Post the codes here and then we will take a close look at the things that can cause this, the least expensive and most likely first.

[Gossamer63]

Thanks, it has new plugs, wires, and rotor. Traced the plug wires and the firing order is correct. I will see about checking the codes but don't have a reader and yes have the check engine light.

thanks again

[Göran W]

You don´t need a reader - it´s built in the DIC. Follow the link under "Cadillac Jim"s Picture!

[KHE]

Simultaneously press and hold the OFF and WARMER buttons on the climate control panel and the codes will appear on the information center.

Did the car accelerate normally before the intake gasket replacement? If so, there has to be something that was missed upon reassembly. It wouldn't hurt to check the timing but if it runs in park, it has to be close. There is a lead that you need to ground to put the engine in the "set timing" mode before using a timing light to check the timing.

[rockfangd]

Just an opinion but Iwould also like to know the before and after.

On the Northstar if you install the throttle body gasket backwards it will not accelerate and will have issues. not sure if this would help but it is all I have at the moment

[KHE]

Just an opinion but Iwould also like to know the before and after.

On the Northstar if you install the throttle body gasket backwards it will not accelerate and will have issues. not sure if this would help but it is all I have at the moment

'92 Eldorado will have the 4.9 engine.

[JohnnyG]

You mention replacing the rotor and wires and plugs, but what about the distributor cap? A carbon track inside the cap can cause this.

[rockfangd]

Just an opinion but Iwould also like to know the before and after.

On the Northstar if you install the throttle body gasket backwards it will not accelerate and will have issues. not sure if this would help but it is all I have at the moment

'92 Eldorado will have the 4.9 engine.

Thanks. I figured it was close

[Gossamer63]

Thanks for all the info and we will get the codes and post them later. It was running rough before the gasket change out that was leaking but had power. When we took it apart it actually had a "modified" north star gasket set, lose bolts and on and on. The inside of the cap looks good, and one other note is my son did not put in the restrictor plate that came with the gasket set, info he saw said to leave it out. We did not remove the throttle body and it is a 4.9. Sounds like it is missing or not firing on all 8. Idles pretty good and you can run it up fine in park. Put in gear and it almost dies or if you try to drive it, push the petal to the floor and not much happens, so under load no power.

Codes: A011 and E038. There is an extensive list of error codes but these are these are the current ones.

Thanks again for the help, forehead is a bit sore from banging on the hood........

[KHE]

A011 is a high side temperature sensor circuit code which is for the A/C system - maybe a sensor is not plugged in on the A/C line. That wouldn't have anything to do with the rough running/no power.

E038 is an open MAT sensor signal. There is a manifold air temp sensor that may be unplugged or damaged.

[Gossamer63]

Thanks for the help. I know the sensor and the plug wires have broken. Could that cause the loss of power and idle issues?

[Cadillac Jim]

Broken sensor wiring mean that the car's computer cannot operate the fuel injection as designed. To keep the car running for safety reasons, the car's computer will throw a code, turn on the "Check Engine" light, and provide the best performance possible with priority on preventing engine damage. Performance, horsepower, etc. are not a consideration in these fall-back modes.

This may or may not be the cause of *all* the problems.

[Gossamer63]

Allrighty, thank you for the help. We will try a new plug for the sensor and see if it fixes and or helps.

[winterset]

When accelerating, and it starts bucking, if you take your foot off the gas, wait a second, then accelerate again, does it let you go faster, as opposed to keeping your foot on the gas where no matter how long, you are stuck in a slow speed, and it feels like a transmission slipping? - by this time, you will be getting random misfire codes.

If so:

You do have the classic symptoms of a plugged up cat. Could be that your car was running too rich, and might have melted the honeycomb in the cat. Also, coolant leaking into the exhaust ports destroys the cats ability to pass gases thru. You might have to be creative on how you can troubleshoot this. one way might be to run a quick acceleration test with the EGR or one of the egr ports removed, as to let more exhaust out before the cat - or maybe remove a pre cat O2 sensor? on another car, I had the entire stainless steel exhaust system removed, and tried blowing a shop vac thru, and it was just clogged up. I broke the inside of the cat with a rod, and the problem was solved. - I immediately ordered a new cat, and all the codes went away, and the car was happy & powerful again.

[Gossamer63]

Sounds similar but we haven't gotten any misfire codes

[PAUL T]

Make sure your Battery terminals are clean & tight. The problem could be the cars computer (ECM). Did repairing the sensor help? You might check the Fuel pressure to check on a weak fuel pump.

[Gossamer63]

Fixed sensors and also put in a new fuel filter, compression from the pipes seems normal. However it is still running extremely rough and seems to be running pretty rich. There is no longer any current codes except for the low refrigerant code. No longer has a check engine light either. Car seems to think its fine but its obviously not. Not sure what to do next, shop maybe? it seemed to run better at idle after i changed the fuel filter and sensor, it stayed at idle smoothly until i drove it, then it immediatly started running rough again and idled rough again after parked.

[Gossamer63]

We have replaced, cleaned and coated the battery terminals, the fuel pump is quiet and seems smooth, if that is a likely culprit how would you go about checking its output?

[JohnnyG]

Have you checked the FPR by pulling the vacuum line off and checking for fuel? The "running rich" part has me concerned. Either the FPR is leaking through or you have an injector stuck open. Fuel rails can be be pulled with the injectors attached, then powered up (not started) in order to check for leaks.

Fuel pressure can be check by attaching the proper guage to the port provided on the line.

[Gossamer63]

Im wondering if the o2 sensors could be what is causing the misfire/rough idle and the loss of power due to putting too much gas into the motor and causeing premaure or late fire.

I have also read that a cracked header could cause this because it will pull more oxygen into the exhaust system and cause a misread which could inturn be causing all of the symptoms? i have an extremely small hairline crack in the headers which leads to beleive it is either this crack or one of the o2 sensors causeing my problem.

[Gossamer63]

Not sure what the FPR is..? and we replaced the o2 sensor and it is running much better but got a code for ISC rpm out of range(E030 or PO30) and a code for loss of road sensing data(i039)

[KHE]

Check the terminals on the distributor pickup module for corrosion. On a 20+ year old 4.9, that can sometimes be the issue of a lot of drivability isues that do not set a code.

[Gossamer63]

so.....here is the update,(old timer have not tried the cat yet) new MAT sensor and plug, new O2 sensor on front header, new fuel filter and codes cleared, service engine light went out and started running better. So off to the gas station for some of the good stuff and a run up the interstate and that is when the fun started. Had great power run right up to sixty and then..........the RPMs started jumping all over the place and the power was well gone. Lots of smoke. Nursed it back to the house and checked the codes, oh and yes the service engine light is back. We now have a E030 ISC RPM out of range. Did some poking around the ole internet and found what it is and it is what I thought by the throttle body. So is this the cause of the erratic rpm and loss of power? Seems like each fix leads to a new broken this or that, I also put a few more dents in the hood of my sons car banging my head on it.

[Gossamer63]

Check the terminals on the distributor pickup module for corrosion. On a 20+ year old 4.9, that can sometimes be the issue of a lot of drivability isues that do not set a code.

are they located in the cap or is this under where the rotor is attached. I cleaned all the terminals and center contact on the coil when I replaced the cap.