Hello folks,

My ride has a refreshed engine and some gremlins

when I hard pressed gas pedal from idle it throw fire from the throttle body

I started with rich A/F mixture, trouble code 14, I replaced map sensor with same results, I replaced tps and troublecode dissappear. But TB backfire and rich mix stills.

double Check firing order ignition wires

Double checked the timing at TDC, rotor pointing to #1 at distributor cap.

Remove distributor and this was the position:





And I moved it a litle bit, near to 12 - 6 o'clock :




according with those 2 pictures, help me to decide what is the correct position. ???

Anyway After that, backfires still.

I tried the manual Sync procedure. I left it close to 5 volts, about 4.98v

Thanks in advance for your help

 

To set the distributor back the way it was(probably nothing wrong with it) #1 cylinder must be on the COMPRESSION STROKE (TDC) Then position the distributor like this(since you moved the gear you need to position that so you can achieve this) Rotor will be pointing to the left near the oil pressure sensor. Your issue is most likely is a bad plenum gasket, Fix is here assuming the cap and rotor are in good condition.

 

Thank you for your answer.
At TDC , My rotor is pointing to the camshaft position sensor Cyl No1 oil pressure sensorside. As your fig. Img.





My ignition rotor is new, because I lost my old one when I removed it to inspect 🙈.

I don't see cracks in my cap on my visual inspection and running at idle in the night I don't see jumping spark either. Here is a picture inside for the contacts:


Do I need to replace it for that?

about plenum gaskets, I forget to mention I'm using M1 4bbl intake manifold (with sealed below side). Since I have a refreshed engine it has new gaskets. and running 4bbl throttle body too.

I'm looking for vacuum leaks, I fix a couple of them with 2 lines, but my backfire persist.

About my first post, what gear position is the correct? The first or the second one?

Thanks again

 

Gear position isn't as important as the distributor being properly lined up on the sensor, which appears to be correct on yours.

4 barrel throttle body?? Which one?

 

As part of the motor refresh, was the timing chain and gears changed/moved? If so, were the crank and cam gears aligned properly when the timing chain was installed?

 

thanks

This is my TB



I bought it used some time ago , it doesn't has brand mark.

I had to invert two wires of the TPS connector because the sensor fits in the opposite direction

 

Right, everything was disassembled. They were installed at TDC. point to point on the gears.

 

Did you verify correct TPS operation in some fashion?

 

Is this still running the stock PCM? You can hook up a timing light and see where it is firing.

 

Well, when We installed TB for the first time, before the engine was refreshed. Was impossible use it because at start it was full throttled with the original tps position. We found in forums a post talking about this situation and the solution was cross the end wires of the tps connector. With this mod everything works good. I never checked voltage. But now, with this situation and your question, I verified and I have 1.62 v at idle and with engine off key on the same value this must be an issue if the original reading should be approximately .060 and maximum a little less than 1 volt, right? I had a Spare sensor, I nstalled and I read the same value. I released the sensor and I can read less volts.

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