so i installed some long tube headers and are running them open at the moment (very loud...but sounds mean)... and once the cars warmed up if i take it on a spirited drive on the highway once i hit 4th at WOT after a couple seconds the engine seems to cut out... the speedo drops to 0 and theres no power at all... almost like the engine shuts off... then the car kicks back in about a second later speedo shoots back up to speed and it seems fine.... do you think i could be experiencing vaporlock because the collector lets the exhaust gases out fairly close to the fule lines on the drive side frame rail.... or does it sound like something else?

 

That is definitly a weird problem but I bet if you posted it in the exaust board section it would get a lot more exposure and you might get some more opinions. You might be on the right track or maybe you have some wires that are a bit to close?

 

wires are all clear.... i have some 1500 degree wire shielding stuff... so i'll try covering my fuel lines and hopefully that helps...but if anyone has anymore insight that'd be great... does it sound like fuel starvation?

 

Possible pickup coil or ignition module affected by heat.

another source could be the passs side head grds. Clean and tighten them

later
Jeremy

 

how would you suggest blocking heat soak from getting to the pickup coil and ignition module?

i'll clean and tighten the grounds tomorrow!

 

Apply new heat sink compound to the ignition module.

Test the pickup coil per the manual

 

thanks will do!

 

check the o2 sensor wire... see if it isn't melted to the header... and if you don't mind me asking... what the hell is Quarter in FPR mean??? is there a quarter in your fuel pressure regulator???

 

yes, he put a quarter in his FPR as to bump the static fuel pressure up.

 

O2 sensor wire is fine... i made sure that puppy was zip tied outta the way... i used my heat shield tubing stuff and wrapped my fuel lines in the area and it seemed fine earlier today.... later tonight i'll try it out and see if the problem comes back since its raining right now...

and yes there is a quarter in my fuel pressure regulator...i was to poor at the time to afford an adjustable one sooo i threw a quarter in and voila... about a boost of 4-5 PSI...i now have another stock one that im going to make into an adjustable....kinda gives a new meaning to throwing money into a car...i do it literally!

 

The speedo is controlled by the computer in 1991. If the speedo goes to 0 and the engine "shuts off" you've got computer problems- either the power supply to it or maybe the ECM itself, but you've got computer problems in one way shape or form.

The ign. pickup or O2 wouldn't stop the speedo from working. And the ECM doesn't even look at the O2 when you're wide open.

 

this may seem too obvious but in "4th gear and WOT" aren't you going to be engaging the rev limiter in your ECM? I can take my car up to about 100 and everything that you describe with the exception of the speedo going dead happens. I'm not sure that is the rev limiter or a speed control that the ECM has in it. I have read that there definitely is one, at least in the Camaros.

 

ummm car is a 5 speed.... had 245/50R16 tires from the factory so noo speed limiter..... the car can do 250km/h aswell so WOT in 4th is not the issue... i did some searching and made another post and what Damon said about the computer so far seems like the winner...