Help! Help me get my engine running smoothly please.

[jotto]

Im starting work on the engine to get her running smoothly but need some help as Im a little unsure where to start if Im honest.

She starts and runs but as soon as I give her any acceleration she dies. I checked that there was a good flow from the accelerator pump which there appears to be so I think it would be best for me to start at the beginning so all tips greatly appreciated.
I did find a post by wajulia that had a long description of what to check and how but for the life of me I cant find it now.

Some info for you to help me.
Air pump is on but disconnected as diverter valve was badly burnt.
3 air pipes blanked off at manifold check valves.

There appears to be one open port at the front of the carb. I believe it is a T pipe with one hose going to the choke pull off and the other port open. When blocked off, it runs worse, when open, it runs better. It seems like it is running too rich and needs more air. Does this connect to the air cleaner when fitted?

Before I tear in to the carb, what should I check.
Is there any online guides to tuning these E4ME carbs as well as checking computer is working correctly.

Also, one quick question, should my choke light stay on whilst the choke is energised? Mine comes on when key is turned to on position but goes out when engine running even though choke appears to work.

Really do appreciate any help.

 

[SVO]

I believe that the choke light being on indicates that the choke isn't energized. I also believe that it gets it's power from the charging circuit, which can indicate that the alternator may have a problem. I base that on helping a friend many years ago troubleshoot his '81's choke light. In his case, he had lost the alternator belt.

HTH

Bob

 

[dwayneroos@yahoo.com]

engine help

Any luck on getting her running smoothly? The diverter valve and pipes were all disconnected from my car when I bought it.As far as the choke,mine lights up for about 10 seconds when I first start it then goes out,those carbs as far as I understand you really can't do much with them. I ripped mine off and installed an after market one and runs way better and much more flexability as far as tuning goes.
Regards Dwayne

 

[jotto]

The choke light doesnt stay on. I thought it would whilst the choke was on but thinking about it, its powered all the time so that wouldnt make sense. Having the light on if the choke is not getting power would make sense but not sure how the car knows as there is only a single cable.
Choke is operational.

Still fighting it.

If the carb needs rebuilding I will. Even with the smog stuff removed, having the computer control should give me better gas mileage.

If all else fails, I have a non computer Q Jet and a new distributor waiting.....

 

[dwayneroos@yahoo.com]

Thats good,good luck and let us know how it turns out
Regards Dwayne

 

[TimAT]

Check your wiring diagram- the choke heater gets it's power from a choke heater relay. If there is a bad diode in the alternator, the choke light will come on. Or if the small brown(?) wire from the alternator plug is broken the choke heat wont' operate correctly. Could be a bad relay. The choke light should come on when you turn the key on and go out after start. IIRC, it's sort of a mis-label on a warning light.

 

[jotto]

Check your wiring diagram- the choke heater gets it's power from a choke heater relay. If there is a bad diode in the alternator, the choke light will come on. Or if the small brown(?) wire from the alternator plug is broken the choke heat wont' operate correctly. Could be a bad relay. The choke light should come on when you turn the key on and go out after start. IIRC, it's sort of a mis-label on a warning light.

Thats whats happening, choke is operating correctly.

 

[Wajulia]

A few questions

1) Is the ECM still in the car and operational? Does the CEL go off at all? Are there any codes.
2) Does the car idle OK?
3) Is your complaint the stumble off idle. Does it run OK after the stumble?

The Stumble, normally it would be the accelerator pump. So things to check:
1) you see a nice spray from the accelerator pump in both primaries?
2) Check all the vacuum lines for leaks or hoses being knocked off. To help to eliminate vacuum issues, You can plug almost every vacuum line in an 81 at idle and it will run (not the one going to the MAP sensor, thin tube at the back of the carb)
3) Timing, could your timing have been changed? Can you check your timing (with the four pin distributor connector unplugged, should be 6-12 deg.
4) Watch the timing with the connector re-attached, is it advancing as you rev the engine -- if no, the HEI module may have gone bad.

Some things to think about -- let us know what you find.

 

[jotto]

ECM is still in car and appears to be operational.
Car does not idle smoothly. MC solenoid appears to be faulty. Went through MC solenoid diagnostics and am getting strange results.
MCS resistance is 22 ohms. Applying a voltage ( 9v ) to MCS does not make it click.
Voltage at dwell lead is 11.7 volts.
Voltage at terminal 18 of ECM is 5.08 volts. Not sure how that works......

Will check connector again but think the ground may not be good at the MCS.

Once started, car will idle whilst on choke but the dies. Because of MCS fault, running very rich.
Accelerator pump produces good squirts.
All vacuum ports plugged except MAP. No codes from ECM, just 12 as normal.
Havent verified timing...wont run long enough to warm up fully and stay running.

Need to re check a few things but need to get carb sorted first I think.

 

[Wajulia]

You can put something light and small (Matchstick like) down in the "D" of the carb (opening just in front of the Idle air adjustment screw). It will be sitting right on top of the MC Solenoid. If you put 9v across the terminals of the connector, you will absolutely see it jump. If not it needs to be replaced. If it does jump, it is ok, there is no in between, either it works or it doesn't.

You can buy another one for a reasonable price. I suggest that if you open the carb to replace it, get a rebuild kit, disassemble and clean. It is not that hard or complicated. If you can not get the carb to idle well it is either vacuum leaks or the idle passages are plugged with dirt or gunk.

ECM is still in car and appears to be operational.
Car does not idle smoothly. MC solenoid appears to be faulty. Went through MC solenoid diagnostics and am getting strange results.
MCS resistance is 22 ohms. Applying a voltage ( 9v ) to MCS does not make it click.
Voltage at dwell lead is 11.7 volts.


Voltage at terminal 18 of ECM is 5.08 volts. Not sure how that works......

Will check connector again but think the ground may not be good at the MCS.

Once started, car will idle whilst on choke but the dies. Because of MCS fault, running very rich.
Accelerator pump produces good squirts.
All vacuum ports plugged except MAP. No codes from ECM, just 12 as normal.
Havent verified timing...wont run long enough to warm up fully and stay running.

Need to re check a few things but need to get carb sorted first I think.

 

[jotto]

Took the carb off the car tonight to see whats happening and will post back with info. Pretty sure MCS is dead.

Quick question.
Will the car start and run with a non computer carb and the comp controlled distributor OR do I need to replace both?
Reason I ask is I fitted a qjet I had on the shelf from my old 75 which was known to run OK but it wouldnt start. Wasnt sure if it was simply a timing issue or if the dizzy has to be replaced to even get it to start. I was thinking with the comp dizzy disconnected from the computer it should at least start.
It turns over and fuel is in the carb. It tries to start but doesnt catch, that why I thought it might just need the dizzy tweaking. Having said that, I suppose the ECM needs a signal from the TPS for the dizzy????

Thoughts? I do have a standard HEI dizzy here on my shelf as well so could fit that but just wanted to do one thing at a time just in case it didnt run so I could troubleshoot just the one issue at a time.
Thanks for the help.

 

[jotto]

The carb is a mess inside but the MCS works! Was a bit sticky but now is very free.
Carb will need a rebuild for sure.
TPS may need replacement. Measuring the resistance across it as I activate the plunger produces very eratic results. Not smooth like it supposed to be.