The "Whats Wrong with My Car" thread

[Dan_E]

Whats wrong with my car?!?!

2nd gear...it pulls strong and hard all the way to redline! (Shift to 3rd) then Hella fasterrr and harder, and boom it jerks like I take my foot off the accel and then slam it back @ WOT. W T F!!!

Brett @ Vishnu suggested it might be the fuel pump. I changed spark plugs, checked injector wires, REPLACED FUEL PUMP TODAY AFTER BEING STRANDED CUZ IT WOULDN'T START. (Walbro 255lph) After I replaced it, it STILL didn't start, I cleaned off the Tec-II ignition timing pickup and it started right up. But the hesitation at WOT is still there.

So basically I think I got screwed on the fuel pump (My own fault)

When sheet isn't working in my life, it F's up my whole mentality. I'm all frusterated and pissy. Someone help please.

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[Dan_E]

Thought: Would the clutch slip off the flywheel like that? Like more power than it can handle. I've had it slip before but it seemed more gradual than the whiplash inducing effect I get now.

What other things can I check?

[Drac9]

Clogged injector maybe? Do you have a fuel pressure gauge? If so, do you notice a dip in Fuel pressure when it happens? Maybe the map sensor is getting a bogus reading. mine acts like that when my MAF is acting up. Plug wire might be bad, causing it to misfire. Have you read your plugs? Does it look like you are running too rich or lean in any cylinder?

[Austin]

How many times has this happened? Do you mash the throttle in 2nd gear, or do you roll on? Does it happen every time in 3rd? Does it happen in 4th?

It sounds like a MAP or TPS accel enrichment. Have you done any tuning lately? Maybe one of your numbers is a "100" where you meant to type "10". Too much accel enrichments can cause the car to buck heavily. It's also possible that your TPS sensor is going out - if it blinks to a different value and then back to your WOT value, it'll trigger all your TPS accel enrichments...

More info please

[wcbjr]

Dan_E, I was having the same problem you are experiencing, I think. My problem happened at WOT in 3rd-5th. When I got up around 4k rpm's the car would completely bog. No matter how long I left my foot on the gas pedal, the car would not go above 4k rpm's, it just kept bogging. Since then I have cleaned and regapped my plugs(smaller), replaced the spark plug wires(Magnecore), and tuned out a LOT of fuel across the board. Hasn't happened since. My bet is you are running too rich for whatever reason, not enough spark, too much fuel, etc.

edit: it only happened at WOT full boost, partial throttle full boost was ok.

[8Complex]

If it doesn't start, there may be another issue. Can you hear the fuel pump run when you turn the key? If no, then there is some sort of fuel pump control circuit malfunction.

Why it would hit a rev limiter of sorts is beyond me, as long as you had your eye on the gauges and saw nothing out of the ordinary. Perhaps an intermittent connection with the main power for the TEC.

[Dan_E]

It'll buck once or twice but then continue to pull hard all the way to redline. It does happen in multiple gears, and I always roll on the throttle, no sudden movements.

I think I'm going to check all the plug wires again, one of the magnacores isn't seating flush with the heads.

I KNOW its running on the rich side...plus my bumper is black right on top of the muffler (Knock=BAD) I haven't touched the engine map for months. I'm going to try and reflash the tec with its current program and see if something got tweeked somewhere.

X out the clutch idea...it even happens at just 5 psi!!

ugh...

[Dan_E]

Anyone know where to get new plug wires besides the $120 "Vishnu cut" magnacores? I need 2 like stock size (1'-1.5') and 2 about 2.5' to 3' long...My Tec is mounted where the battery used to be.


...And thanks for the input eveyone!!!

[Austin]

Make sure all ground connections (especially ground to the coils) are extremely tight and seated. Loose coil ground connections can cause misfires and misfire like symptoms.

[BOY]

DanE, you could make your own wires. Check out scoobymods.com for a write up on custom MSDs. I can tell you this, you can make 2+ sets of wires for less than the price of stock or Magnecores but you will have to play with the spark plug gap due to the MSD's low resistance.

[Revision]

Post your current .bin file and a current .dat file for us to examine. There are too many variables to answer your question.

[jdk]

Sounds EXACTLY like your hitting your max kpa value on your tec...you can either bump the "kpa cut" a little higher or turn the boost down

[Dan_E]

Turn the boost down? But thats no fun!

Whats making me mad is its been running PERFECT for months. Haven't touched the tec map for about the same. Now when I tried to do a datalog run last night, my laptop (ghettotop) decided it didn't want to load Win98 after I had used it flawlessly that morning.

Oh...and I bought the $120 wires from vishnu, went to go mash on my favorite backroads, and no problems what-so-ever. At one point I went through 3 full gears (2-4) @ WOT without a hiccup. Got home, parked the car for a few hours, left again, allowed a good 10 min of normal driving to bring temps up and all, and the original problem presented itself once again.

This is a bad start to the new year. I'll try to get a log file to post. Stay tuned, and keep the suggestions coming. Thanks again all!

[Dan_E]

OK FINALLY! some progress! I have a log file and my calibration files for the Tec. You will notice the nice steep drops while the TPS still shows the pedal is to the metal. It was a 2nd 3rd and 4th gear run.

Thanks to TOMMY for hosting while I'm trying to communicate on a ghetto computer

______________________________________
Data log with WinTEC2 v2.0.6
www.daporkchop.com/dan/ggggg.dat

Calibration Map files
www.daporkchop.com/dan/tweeker.bin
www.daporkchop.com/dan/tweeker.s19

[jdk]

...allright...I'm assuming you have a 2 bar map sensor? Check your MAP sensor parameters under high voltage failure...if its under 4.67v...thats your problem! According to your map reading in you datalog your spiking too a little over 12.5 psi.

[Austin]

jdk is right on the money.

You have a 2 bar map sensor. Your MAP sensor high voltage failure is set to 4.5 volts, which is right at 182kpa. Your failure default setting is 20kpa.

Both times in 3rd gear your car stutters, you're boosting just over 180 - 185kpa the first time, and 182 kpa the second time. Both times your MAP reading in the next data frame is 19.70kpa, which is causing your problems.

Fix: Set your MAP sensor high voltage failure at 4.95 or 5 volts. Mine is set at 5 volts.

[Dan_E]

If you guys are right, I'm going to shoot myself in the foot

BRB...Gunna go for a drive

[Dan_E]

Seems to be fine now?! I did turn down the boost a smidge, 12psi boost spikes = ALL bad!

I'll stay posted...Dyno #'s coming soon