Okay......having major issues and needing help. My 84 GSL-SE has been giving me issues for a while now. I've tried several things on other's posts, but still having the issues.

She starts and initially runs fine, but afte bout 3 minutes, she starts to backfire and stumble at above 3K rpm. Speed doesn't seem to matter, neither does gear selection. After the problem begins, I can only use about one inch of pedal travel to keep her going....anything more and she falls flat on her face. The problem seems to occur mostly during loaded operation, though occasionally I can get it to stumble at idle around 5K and up. This used to be an intermittent problem, occuring only in the afternoon, on my way back from work, but now (as mentioned) every drive after 3 minutes.

Here's the things I have done:
New fuel filter
New TPS (adjusted correctly via double light tester)
Catalytic converters (pre and main) removed, muffler gutted out
5/6 actuators working correctly (welded pipe at angle into straight exhaust)
New fuel injectors and electrical connectors
New fuel pump
New fuel lines (hard and soft)
Fuel pressure regulator tested and passed
Coils tested and passed
New spark plugs
Checked for vacuum leaks (via carb cleaner spray).... none found
New in tank fuel strainer
Cone filter in fuel line removed and pre-filter installed
Fuel pressure checks out
Fuel volume checks out

I know somebody here can help me figure this mess out. I need this car running again......My '75 Dodge 440 CrewCab is killing me in gas mileage (60+ miles/day).

Thanx in advance
Cameron

 

Did you replace the ignitors on the distributor? They do fail, and this is about how they fail.

 

Does it start right back up every time or does it need some coaxing ??

 

do you a header? Either way check the gasket. If you have a leak or crack there it could expand when warm and itll give your car some fits.

 

Starts back up, but very rarely holds a good idle.....if it does hold an idle, it will continue to be symptomatic as soon as put in gear. When this first started, I could shut it off and wait approx 10 minutes and could drive for 15 to 25 mile without incident, but now it does it after anything less than an overnight rest.

 

I have not checked the ignitor or the exhaust gaskets. Will do both of these tomorrow afternoon. I haven't searched yet, so pardon the question, but is there a test for the ignitor?

 

There's a test for the ignitor in the Haynes manual and FSM. Probably also a search in the 1st gen forum, or even in the FAQ as well.

 

Tps??

 

suggestion- check coil voltage at start up and at three minute mark. I had a weak fuseable link dropping voltage that caused a lot for running problems on my new engine. just a thought.

 

sounds like a tps sensor to me , re-check the tps and make sure the resistance is correct its in the Haynes Manuel as well . or try all data . And the ignitor are common to fail as well .

 

TPS is new to this car and was tested previously. Well within specs, and adjusted with 2 light tester. This was my initial thought as well. I will be testing ignitor soon....and keep y'all posted on results.
Certainly appreciate the help thus far. I was getting real close to selling the car as the frustration with this issue mounted.

 

Ok....Update. Got the ignitor out and tested via two different schematics found on this site. Passes one, fails the other.
The schematic used that shows an ignitor failure is by Rich

https://www.rx7club.com/attachments/...itortester-jpg

The other one that it passes the ignitor is by Mar3

https://www.rx7club.com/1st-generati...t=ignitor+test

They are each a little different in their routing of wires......so I guess, I'm still wondering if the ignitor is good.

which schematic is most accurate?

thanx in advance
cameron