Car won't run - Big Brain help needed!
 

Filled the tank. Drove 40 miles down the freeway. Turn off, drive a little further, cross some railroad tracks with a stop sign just past. Before coming to a complete stop the car dies. Temp fine, oil fine, gauges working fine, tach, etc. Car won't restart, doesn't want to fire. Get picked up to get to the B-day party I was going to.

Come back a couple hours later and the car fires but won't continue running when I stop cranking. Fires for a second and dies over and over. Tow truck time. Drop it at a shop since I work 60 hour weeks and this is my primary vehicle. At the shop the next day it now fires up and runs for maybe 5-10 seconds, not just during cranking but after 10 seconds it just quits.

Really strange how it went from not starting at all to firing for a second to running for a few seconds over a 12 hour period without any real work being done on it.

Here's a datalog of starting, running, dying a few times...

Attachment 15627

I checked as many grounds as I could find easily. Unplugged and plugged in connectors and relays. Checked fuses. Checked and fiddled with all the connections for the COPs.

Looked at Mnet threads about similar issues but of course that's mostly about stock cars, not turbo'd, MSPNP, aftermarket COPs, etc. My list of possibles includes, injector relay, FP relay, CAS, grounds, fuel filter, fuel pump, FPR, ignition, broken wire, loose connections, corroded contacts. etc.

Before I have to pay the shop to go through each and every last possibility I was hoping someone might see something in the datalog or my description of the trouble that might give me a clue what to look at first. Electrical gremlins are the bain of my existence, I don't have the slightest idea how to go about checking continuity, resistance, etc so I have to pay others do do it.:loser:

Narrowing things down could save me a whole bunch of cash on Monday when the shop starts looking at it.

sounds like a fueling issue. at least that's the impression I get from it catching and dying. you can try squeezing a fuel line to make sure you have pressure when the car is in "run".

Check the fuel filter.

What is up with the map reading???? 414??

When I open your datalog it shows your map shooting up to 414 kpa, with your PW dropping to zero at the same time. If my MLV is interpreting your log properly that is.

Other than that do a fuel pressure check, check for spark. See if the plugs are fouled.

If thats all good, it's possible you may have bad gas. While you're hooking up the fuel pressure gauge drain some fuel into a clear empty water bottle to check for water in the fuel.

+1.

I think I had similar issues when I forgot to hook up the MAP vacuum line after taking the MS out of the car. Double check nothing popped off or melted. Also might want to try the quick, easy, and free "fix" of reloading firmware and .msq.

Although if the map line was bad, you'd get what, 100kpa? Certainly not 414. Do you even have a 4 bar map sensor?

its possible the MAP sensor is bad. Ive had to replace two last winter (not mine) after water froze in the line and then killed the sensors.

Sorry to be slow getting back in with all these suggestions. I'm at work right now and have had a run of customers in the showroom - thankfully!!!

I didn't even notice that map reading. That's why I needed all you good, dedicated, helpful, knowledgeable, smart, great looking people helping out! (enough ass kissing as a thankyou yet?) It's definetely getting spark and SOME fuel, the thing starts and runs for a bit. Something is killing spark or it's not getting enough fuel. The outlandish MAP reading puts me into hard cut overboost protection which could explain the dying.

Looked back at the 2 other datalogs I did and all of them read the same 414 max. Looked at my last datalog when it was running right and it was scaled properly and not reading that ridiculous figure.

Looks like #1 will be swap the fuel filter per Sav & Rafa because it needs it anyway whether that's the problem or not. #2 will be check the vacuum line as per Curly. #3 check/swap the Map sensor per Brain.

If it's the MAP sensor, any suggestions where I could find one locally? Radioshack/Frys/electronics store or definetly mail order?

Will update Monday if and what the fix was. Don't let that stop anyone else who see's something or with other ideas from piping up though! The more the merrier.

As always BIG THANKYOU!

PM your address and I'll mail you one. they are $28 at diyautotune.com, or available at digikey and alike; I have plenty of spares.

Brain, how many of those map failures have been on MSPNPs? Casey, I'd put my suggestion as #1, much easier and cleaner than replacing the fuel filter. For that job, if you don't have two pairs of vice grips, go buy another (or two) pair right now, because no, you will not be able to change it out that fast. Also, don't forget my firmware/.msq reload suggestion, you never know how important a simple line of code is until it gets screwed up.

I heard of one or two MSPNP failures. Then Newbsauce has issues last winter, he parked it running well and the next time he drove it it was horrible, the MAP sensor log looked odd. He found condensation in his MAP line and I swapped it out and it run great ever since.

After actually looking at your log, change your map sensor first. 414kpa = fux0red.

Deleted. Forgot to refresh the page, and wrote something Dumbass.

New list then guys.

#1 reload ms. free and easy.

#2 check Map line - free and easy to do.

#3 swap in new Map sensor. Most likely cure.

#4 fuel filter in spare time.

Trouble is this is my daily driver. I'm renting a car until it's fixed and it's locked in the shop of the garage I took it to until Monday.

What engine management do you have?

Mspnp.

Ah gotcha. Map sensor shouldnt be a huge challenge to change out then although i've never looked inside a mspnp before. Assuming its in the same place on the 3.57 board as the V3 board you'll just need to get good at desoldering.

Need to borrow my MS? I'll be at Old Chicago tonight around 6pm for an hour or two, I could bring it there if you respond quickly enough. Braineack will have to tell you whether the PNP harness he built for my '93 will work on your '94. Easy diagnosis and my cars down until I get my turbo PCV valve in anyways.

Curly,

Thanks for the offer. Obviously didn't see it in time. I'm off to pull the car out of the shop and see if it's just the MAP line. It'll be a day or two before Brain's sensor gets here to swap it in.