REDTOP RUNS LIKES ASS

SON240sx Automotive
1

Ok, so I really didn’t want to do this but I need to ask for some input, I have been trying to diagnose this sr for days and sadly, I’ve HAD NO luck in finding the problem… My brain is fried and I’m hoping I’m overlooking/neglecting something.

Original issue was a no start. After a rainy day, I go to crank the car and it doesn’t start. Keep trying and it’s a no go, I’m late for work and I leave it. Go to start it the next day and voila, cranks up right away. Turn it off and try again a couple times and it seems to be ok, so I go in and eat some breakfast and come back out 10 minutes later. To my surprise car doesn’t start… wtf…

Tow it to my shop test and it seems the no start has sorted itself out. Car has started up since the weekend but now it’s running like a bag of shit…
It’s missing and cutting out in the higher rpms, and it stalls if the revs aren’t kept up.

Here’s what I tested so far:
Continuity between ground circuit and power circuit on injectors
Injector pulse
Injector impedence
Fuel pressure
Spark
Vacuum leaks
ECT resistance
Swapped CAS/ignitor chip/ECU
Checked grounds, fuses
I’ve cut open the engine harness to check for corroded wires

Bottom line I have fuel/spark/air

Also I’ve check for timing but I’m not sure if it’s off cause it’s running like shit, or it’s running like shit because it’s off. Can’t get it to idle so I sort of neglected that as an issue for now.

Thoughts anyone?

2

Is the fuel pump priming and holding pressure while driving? The no start after some driving could be vapour lock on the rails, “hot start condition” as they call it, but breaking up at higher rpm could be the pump not keeping up or even spark problems at boost (wrong heat range, wrong gap)

3

when you say it doesn’t crank over, is the start motor working? Check your wire’s going to the starter, the main power/charging circuit runs through those wires.

4

There’s fuel pressure at all times, I already confirmed that and car starts but it stalls/idles rough

5

any cracked coil pack?

6

… I think I’d notice a coil arcing. Besides… one cracked coil wouldn’t cause stalling.

7

My Top 3 SR Guesses Are:

  1. Knock Sensor (Had this issue with it cutting out at above 3000RPM)
  2. Faulty Injector (Had this issue where 1 was no good and car would only start if you let it sit for 2+hrs, I think had something to do with flooding)
  3. Coilpack Grounding From the coilpack main harness issue

Good Luck Chuck!

8

You mentioned that it was a rainy day. Maybe moisture got into something old. check for cracks, holes, and generally spots for moisture to get in or evidence that moisture has been in that area. Check the ignition components specifically. Improper/poor ground could be an issue, take the grounds off and sand the rust/ oxidization off of the connection.

9

Funky timing, cas was installed correctly but I guess the motor didn’t like that. Had to retard it a couple teeth. Starting issue was intermittent, fixed a semi-corroded wire. I got this lol