Sudden loss of pwr, then no start

sneed21 · 03-13-2004, 07:15 AM

Going home from work Friday, I was cruising at 70mph when all of a sudden it felt like I was riding my brakes. I coasted off I95 and couldn't get the rpm over 2K or the engine would bog and die. The car idled fine, but wouldn't rev over 2K. I checked all connections, and pulled the cap (cleaned it) and the car ran fine, reved correctly, but it only lasted for about 5 min and then the car went back to bogging. I had it towed home and now it won't even start. It fires up for 2 seconds then just dies. I've also got an '86 so I've been swapping parts to determine what it could be. So far I've checked/replaced. AFM, plugs, plug wires, coil, cap, rotor, and the fuel DME relay. Nothing has helped. I've checked the belt, no teeth missing, and it was replaced less than 500 miles ago. I'm about to check the TPS, but would that keep it from starting?

I'm about to swap DME's................

Thanks for any help!

Sabyre · Sabyre's Garage

Does the cap and rotor need replacement? Were the contact points flat, smooth, gouged?

Seems odd that it ran fine after a clening of the cap. Maybe related.

SoCal Driver · SoCal Driver's Garage

Check the coil to dist HV wire. Could be loose inside the weather boots.

sneed21 · 03-13-2004, 04:16 PM

Replaced cap and roter, and plug wires (including HV coil to dist). Fuel filter has also been changed.

Would a bad TPS affect the car to the point that it would fire and then die instantly?

Reference sensors?

Sabyre · Sabyre's Garage

Definately sounds electrical. How are your grounds?

Roger Hall · 03-13-2004, 08:50 PM

Fuel Pump?

vital-transform · 03-13-2004, 10:19 PM

check the other 2 coil wires too

justin · justin's Garage

Could be the coil getting hot and breaking down.

sneed21 · 03-14-2004, 09:51 AM

Replaced coil, checked coil wires, checked gounds....no improvement. I will be checking the fuel pump today. Any additional suggestions?

justin · justin's Garage

I guess the set screw in the rotor is tight.

asudds · 03-15-2004, 04:21 AM

Also check to be sure the temp senders are plugged in, mine worked loose and caused a no start when cold and very rich condition when hot.

Aaron

sneed21 · 03-15-2004, 04:29 AM

Yes the roter set screw is tight......don't want to lose that small thing! I'll check the temp sensor leads.

This has really thrown me for a loop.

sneed21 · 03-16-2004, 04:38 AM

OK, I've finally worked up the laundry list of things I've checked and or replaced....to no avail....

Replaced Coil
Replaced Rotor and Cap
Replaced Plugs
Replaced Plug and Coil wires
Replaced AFM
Replaced DME
Replaced DME Fuel Relay
Jumpered Fuel Pump (and the pump ran)
Checked sensors for tightness and connections
Checked TDC and belt conditions......they were fine
Injectors are working.

Got the car to start but it ran really, really rough and rich, then died after about 30 seconds. Almost like it was flooding out, or had a dead cylinder. Checked for spark, and it was good across all.

Again, no answer to my question about the TPS keeping the car from starting?

Next, I will check the fuel pressure at the rail....and a compression test.

If I can't find anything tonight, I'll have to get it towed to the shop.........

vital-transform · 03-16-2004, 04:47 AM

try the referance sensor adjustment and FPR

sneed21 · 03-16-2004, 04:53 AM

Checked the ref sensor and it is tight, I'll have to check the shop manual for adjustment if necessary. The FPR will be checked tonight.

sneed21 · 03-17-2004, 05:06 AM

Checked FPR , Damper, ref sensors, and rechecked all values at all sensors, Ohms, and V. Everything was w/in specs. As mentioned, I've changed the DME, but I'm not sure of the compatibility, as the 85.5 Euro version is 944.618.121.01 and the one off the '86 is ".04". Also, and this is what scares me....., there is an EXTRA Motronic Box hooked up with the wiring. It is a small (about 1/3 the size of the DME) plastic box labeled "Motronic II". There is a 6 wire connection and plug coming off of it "snapping" into the wire harness. Possibly done when the car was converted to US specs??? Also, there is the small black alarm box. I'm at my wits end and am going to have to get it towed to the local Euro shop to see if they can do any better. Maybe I'll just part it out........

Any thoughts? Ya'll think I can make back my $2500 investment if I part her out? Maybe a Euro Bumper Conversion for my '86??, or for your 944??

The VERY Dazed and Confused,

sneed21

SoCal Driver · SoCal Driver's Garage

When the euro 944 is converted to US specs I think they add the O2 sensor and wire this into the DME engine temp circuit. Thus the additional box. Then this just may be the alarm. Have to trace the six wires down.

sneed21 · 03-17-2004, 06:07 AM

Your right, I've traced the wires and it does go to the O2 sensor. Plugging, or unplugging the "extra" box doesn't change anything. There is also an extra box for the alarm.

SoCal Driver · SoCal Driver's Garage

You need to find out where it has intercepted the engine and/or air temp sender wires to the DME and jumper these. Most likely the DME engine temp sender.

sneed21 · 03-17-2004, 06:23 AM

Thanks SoCal.........I appreciate the info......It's going to drive me nuts till I can get off work to go check. I don't like to give up, but if this check doesn't work, I'm having it towed to the shop. If the diagnosis and fix ends up being ridiculous, I'll just part it out. It's an automatic so no big loss and I'd like to give my '86 5 speed the "Euro Look" anyway.