3800 rpm wall/ hesitation

[Apex944]

Originally Posted by WE3RX7

How worked over is this car? Motor swap, etc done by previous owner when you picked it up?

The standard "stumble" that many FC owners had at 3800rpm was the bad ground as was mentioned above - you're describing something different.

When you hit that "wall" does the car just simply bog down or shut off?

What color are the secondary injector tops? Are you sure they are S4 T2 injectors as appropriate for the car? Does the check engine light come on at all during any of the symptoms?

I'm just trying to weed out a few things in my mind - its just all to common (especially these days w/ all the "drifter" scenes running around) to pick up a frankenstein car that somebody butchered and now you - the good owner, is stuck with figuring out what they did!

The car was pretty messed up when I bought it a little over a year ago.
I myself went through the entire engine wire harness and re-wrapped and repaired it all to a useable condition. I also rebuilt/modified/upgraded and installed a 13BT Series 4 engine into the car. Was well worth the $900 I paid for it though haha. Spare vert rims, parts, most of the engine parts were re-usable, drivetrain is all good, suspension is good, only a few dings/dents here and there etc...

When I hit the wall it backfires/misses/shakes like it's running out of fuel.

It has the correct injectors but does not have a check engine light because it's an '88 S4 which did not come with a check engine light.


I found the problem though

Me and another member who lives near by came up with the idea of grounding out the secondaries via the wire harness off of the ECU while the car was running and to feel/hear/see the a/f ratio of the car.

So car running, holding it at 1500 rpms, tap the front secondary ground wire on/off of a good ground. Yep, it bogs down and goes rich. Do the rear secondary...nothing happens....try again....nothing happens....clogged injector in the rear secondary.

Going to go have a nice talk with the guy who supposedly cleaned them for me....heck, I dont really feel like trying to have him do them for a 3rd! time so I might send them out to witchhunter.... Long story short when he "cleaned" them the last time he said his machine could not fully flow them but they were "good"... WTF he was on I have no idea because if his bench cant flow 550cc's then he shouldnt even be doing injectors.

But yeah, thanks for the help everyone.