I'm SO Freakin' Frustrated!!!!

[silverbullet]

I can't get my car to run right! First, i removed all emission equipment per the threads on this site. I installed a Edlbrock 2101 manifold with the stock carb, distributor and ecm. I installed long tube heddman headers and put in a heated O2 sensor since it is farther back then stock. I put the distributor back in after installing the new intake and had # 1@ TDC. I have the timing set @ 8 BTDC. It runs rough. When i hook the ecm back up after setting the base timing it runs even worse. It idles @ about 700 rpm's and then when i shift into gear it cuts off. I have the unused vacuum ports on the carb plugged. I don't know what to look at next.I have had every backyard mechanicover andthey get now where. Anybody have any ideas???? Desperate!!!

Thanks
Bill

 

[damoroso]

Bill,

Sorry to sound obvious, but have you rechecked your firing order? It's easy to cross up a couple wires. Any back firing or popping back through the carb? I've had it happen to me..

David

 

[silverbullet]

David,
thanks for replying. I checked all the wires and they are hooked up correctly.

 

[minifridge1138]

Elaborate on "It runs rough."

 

[silverbullet]

It wo'nt sit and idlevery long before it dies, When it does shut itself off there is some back pressure that comes up through the carb. If i try to put it in gear it dies right away.

 

[silverbullet]

I re-set engine to TDC, re-installed distributor. Set base timing @ 10BTDC and it runs great. I then plug the computer in and it runs very rough and then dies. It restarts immediately and and runs rough ( shaking..bad idle...), I then tried to put it in gear and it immediately dies. I unhooked the ecm again and it runs great and idles @ about 700 rpm.

Anyone have any ideas????

 

[gmjunkie]

I re-set engine to TDC, re-installed distributor. Set base timing @ 10BTDC and it runs great. I then plug the computer in and it runs very rough and then dies. It restarts immediately and and runs rough ( shaking..bad idle...), I then tried to put it in gear and it immediately dies. I unhooked the ecm again and it runs great and idles @ about 700 rpm.

Anyone have any ideas????

Yeah,How bout unplugging the ECM and resetting the timing to 0 BTC and then plugging the ECM back in and seeing what it dose!!

 

[silverbullet]

i set it back to Zero and plugged the ecm back in. It continues to to run and will run in gear but it doesn't sound like it is running smooth. i'm going to try and drive it and see what happens.

 

[silverbullet]

runs horrible!

 

[gmjunkie]

runs horrible!

Check the wiring plug on the carburetor,Make sure that it is getting a good connection!Also did you ever have the carb upside down while you had it off?:confused

 

[silverbullet]

All wiring is good.The carb was never upside down. I just changed the fuel filter and it still runs rough at idle. What was your thoughts with the timing set to zero without the ecm? I thught that the timing was suppose to be set @ 6 BTDC without the ecm hooked up. Many people on this forum recommend 8 -12 BTDC. any thoughts?

 

[gmjunkie]

All wiring is good.The carb was never upside down. I just changed the fuel filter and it still runs rough at idle. What was your thoughts with the timing set to zero without the ecm? I thught that the timing was suppose to be set @ 6 BTDC without the ecm hooked up. Many people on this forum recommend 8 -12 BTDC. any thoughts?

Well,I just wondered about the carb,because sometimes people turn them upside down to dump the gas out of them and stir up crap in the float bowel!!On the timing,I'll let you know,I can't find my 81 Service Manual! Still Look'n!!

 

[Hib Halverson]

First, let me say that when you pull the timing wire, you are not "disconnecting" the ECM, you are disabling the ECM's ability to control spark timing and allowing the engine to revert to base timing (8° BTDC in your case).

Questions:
Are you sure the timing mark on the balancer is correct?
Have you run a compression check.
In what condition are the rest of the ign. parts?

When the timing connection is made, what is the spark at idle?

When you removed all the emissions eqipment, did you remove the EGR. If so, was the calibration altered to allow the engine to run properly at part throttle with no EGR?

When you removed all the emissions eqipment, did you leave or remove the MAP sensor?

Have you diagnosed the engine for vacuum leaks?

 

[Sensei]

First, try setting the idle a little higher for now while you check things.

Check for vacuum leaks. Take a peice of vacuum hose. Put one end in your ear and hold the other close to areas where there may be a leak, pay particular attention to the carb. Here is a stupid thought: I once re-installed my carb with the base gasket upside down and the car barely ran (and I work on the thing myself all the time, so this could happen to anyone).

I disconnected my AIR and EGR and made no adjustments or provisions and had no problems.

Timing should be set at around 10-12 BTDC with the 4 pin distributor connector disconnected. 6 was for emmissions stuff, the car will run stronger and use less fuel with more advance.

Have you checked trouble codes yet?

God bless, Sensei

 

[schweng18]

Definitely check the timing mark on the balancer, when I changed my intake I had the same problem. Came to find out that the balancer had slipped due to age, small block chevy engines are notorious for this. I changed the balancer and set the timing problem was solved.

 

[GerryLP]

a lot of the suggestions here are right-on, and the only way to get through this is to try each one of them.

Vacuum leaks are the paramount cause. But since vacuum leaks are tedious to isolate, please ensure a few things.(when I lose my way, I go back to square one to regroup)

1) Find again top-dead-center, and verify that the #1 wire electrode is aligned with the rotor under the rotor cap. And like Sensei said, while troubleshooting, you can get away with a little higher timing.

2) If you messed with your idle screws, reset them to 3-1/3 turns from bottoming (light pressure when bottoming clockwise, and then go counterclockwise 3-1/3 turns).

3) Concentrate on the vacuum leaks now. A vacuum leak will cause a lean condition, which in turn, causes the backfiring you experienced.

a) While at idle, the engine is running primarily open loop before it warms up, so wait until the engine cools off to isolate it from computer input.

b) Bad wires will cause it to run rough as well, but first, complete on step 3 above.

Re-group, and start over. When frustration set-ins, one can feel like going in circles and not know which way is up.

4) Bad fuel can make it run rough as well. If it has sat around for while, add some fresh fuel to the tank. Get in the habit of adding a fuel stabilizer to the tank before a project and run the engine with it before tearing into it.

5) work on some of those other suggestions. If your MAP sensor is disconnected, it will send the computer into a turmoil, for it is trying to adjust for the last ambient pressure (vacuum signal) last known.

Let us know if you found the culprit or problem...

GerryLP:cool

 

[silverbullet]

I appreciate all of the responses. i went back to square one. i have reset the engine to TDC. #1 lines up, I installed brand new spark plug wires. Timing is set @ 10BTDC with 4 prong wire disconnected. I took carb off and replaced the gasket. All vacuum hoses are hooked up correctly. I will check for leaks next. Thanks for all the input. I will update this weekend when I can check for leaks.

Thanks
Bill

 

[silverbullet]

I have checked for leaks and have not found any. The car idles great and smooth without the 4 pin connector disconnected. Once I connect it it idles rough and then dies out. I have all emmisions removed per the thread on this site. I left the cannister attachedasit suggested. I am not getting any check engine light issues and no codes. Any suggestions???

 

[Sensei]

There is a EST diagnostic flow chart in the GM Service manual. I have no way of posting it here, maybe someone else can, but you need to own this book if you plan to work on your car. Here is the book on ebay, but the price seems a bit high:

http://cgi.ebay.com/ebaymotors/1981...VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

I saw them going for about $40 when I was looking a couple of years ago. I was patient and got one missing the front cover for $9.

If you don't have the book yet, you can start here while you get one:

Did you clean the connector to your ignition module? (in the distributor) Do NOT remove the module from the distributor, but unplug it and clean the connections with Caig Deoxit.

Possible solutions for your problem are:
-Bad connection to, or bad ignition module.
-Various wires that may be shorted or disconnected, Do an inspection at the distributor, ECM and in any areas where you were working when the problem started. Here again, the manual will tell you which specific wires to check as you go through the chart.
-Faulty ECM.

The good news is that none of this is too expensive to fix, but without the manual to guide you step by step, it can be frustrating. i.e. It is easy enough to just go out and replace the ignition module, but if that does not fix it, you wasted $20 and an hour of your time. You don't have to do that too many times to start pulling your hair out. GET THE MANUAL!

God bless, Sensei

 

[GerryLP]

I have checked for leaks and have not found any. The car idles great and smooth without the 4 pin connector disconnected. Once I connect it it idles rough and then dies out. I have all emmisions removed per the thread on this site. I left the cannister attachedasit suggested. I am not getting any check engine light issues and no codes. Any suggestions???

Ok,

So...

no vacuum leaks
No ignition problems (i.e. bad wire, bad module)
You idle mixture needles are good
You still have your manifold sensor hooked-up


Did you disconnect the battery and let the computer drain its saved values? When the battery is hooked, the battery will get new numbers when you start it.

GerryLP:cool