Ep85 backfiring on idle

T

tip

Member +
Hello,
when I start my starlet it begins to backfire lightly on idle.
It starts fine and idles fine.

The old engine was damaged, and now we have put in a 5e with 4efte pistons and.
I have also wired in a AEM fic it starts fine but also backfires on idle.
I plugged in the jumper harness I got from AEM so now I'm running on the stock ECU.

I have set the base ignition timing on the dizzy at 10* BTDC. is this good for 5e?

I have new spark plugs and leads (NGK), I cleaned the dizzy cap, there are no exhaust leaks.

what could cause the light backfire??
 
dac69er

dac69er

Super Moderator
Timing out. Valves not seating properly (not shunned correctly, bent valve etc). Bad wiring connection. Vacuum leak. Dodgy sensor. Tps playing up or badly adjusted. Head gasket gone between cylinders. Poor compression (rings, cracked piston ringland etc)

Could be quite a few things. Any other symptoms?
 
T

tip

Member +
dac69er said:
Timing out. Valves not seating properly (not shunned correctly, bent valve etc). Bad wiring connection. Vacuum leak. Dodgy sensor. Tps playing up or badly adjusted. Head gasket gone between cylinders. Poor compression (rings, cracked piston ringland etc)

Could be quite a few things. Any other symptoms?
Click to expand...

I made a movie of the car idling:
https://www.youtube.com/watch?v=vdOXtPEq1o0

which timing could be out? mechanical or dizzy timing?
I don't hope that it's a bad cylinder head because the Guy whom I bought the engine from said that he reconditioned the head;
where could I check for the bad wiring conecction? when I installed the fic I soldered all the wires.
no vacuum leaks the car idles fine
I dont hope that it's bad rings or cracked piston ringlands because as I said before the guy where I bought the engine from said it was reconditiond not long ago.

I'll try to check the tps tomorrow and see what happens.

Thank you very much for the reply.
 
dac69er

dac69er

Super Moderator
cant watch movies at work so will have to look later. most likely the cam timing. if you have set the static ignition timing via the distributor correctly that rules that out.

you said it misfires on idle but runs fine on idle, which one is it?!?!

i wouldnt always trust what someone tells you if they are selling you something, plenty of dodgy people about. it also may be a completely legitimate mistake and he didnt realise there was an issue. was the misfire still there when you first fitted the engine without the FIC?
 
weeJohn

weeJohn

Lifer
Have you done a compression test on the engine, does it appear to be loosing any cylinder pressure?
 
T

tip

Member +
Hello,
I have checked the TPS and it was off. When I put the 28 thou feeller the multimeter showed 0.02.
I adjusted the TPS and the problem went away for a few seconds lol.
I plugged in the FIC and it does it sometimes..., So I think it's an electrical problem?

dac69er: The mistake we made is fitting everything in one time. the crank had to be undersized so we did that and torqued the crank.
the gearbox was also damaged we opened it up and fixed that to a shift fork was broken. and I also installed the fic.

Weejohn: I'll check the compression tommorrow maybe.

I drove the car yesterday (after longer than 2 years lol) it felt good

Thanks for the replies guys. I'll keep you informed.
 
dac69er

dac69er

Super Moderator
Double check the tps now everything is tightened up. Sometimes it can move slightly when you tighten it all up. it is pretty sensitive.
 
You must log in or register to reply here.
Top