'91, Cranks but No Start (and radiator fan runs?!)

[RussMcB]

My '91 has not started for a few days. Below are all of the possible clues I have gathered. Any help is GREATLY appreciated.

1. No stored codes (just blinks 12's)
2. When cranking, no RPMs show on dash
3. No fuel pressure
4. Have spark (I've only checked cyls 1 & 3 thus far).
5. When I turn the key to On, the driver's side radiator fan runs constantly (and it's loud enough to prevent me from listening for fuel pump humming). This seems odd since I think the fans should only come on at certain temps.
6. One week ago the car was running great after new injectors, coils, Haibeck chip and disabled secondaries.
7. The night before the "no-start" the car stumbled/hesitated several times during a 10 mile drive. With each stumble, the center dash would light up, then go back to normal pretty quickly. It seemed to happen during light throttle/coasting. At one point the engine died completely and I coasted into a parking lot. After a few minutes it restarted and seemed OK until I got home (I drove it pretty gingerly).
8. All fuses near the passenger door are good. (Are there others I should check in other locations?)
9. Recently I purchased a VATS bypass from Eckler's, but have not installed it yet.
10. I've pressed very hard on the clutch pedal, but that does not help. I have not yet tried to bypass the clutch switch.
11. The battery condition is good (I have a load tester). It has been on a trickle charger so it's topped off.
12. New (rebuilt) Bosch starter installed recently.

I have the FSM and have tried to read the troubleshooting steps but find it extremely confusing.

I'm hoping someone can chime in and let me know if the clues above rule out some possible causes, and point towards certain systems I should check (and how).

I'm prepared to spend money on a scan tester, but not really sure it will identify the problem.

Thank you.

[gbrtng]

fix #3 first ...

[max76]

If you have no fuel pressure it's impossible start up the engine

[Paul Workman]

If fuel pressure is nil, of course that is an issue. SO! Starting with fuel delivery:

You can see if the pumps are at least drawing the right current by using the diagnostic connector - a red wire with a black connector poking out of the large wire loom, just to center of the ECM.

With the switch OFF, the current draw between the (pos) terminal of the battery and the diagnostic connector should be 4-5 amperes per pump, or 8-10 total with both running.

If in fact you have the proper current draw, you should be able to measure approx 55 psi at the Schrader valve (located at the front end of the passenger-side rail.) If not, the delivery circuit comes under suspicion; starting with the hose connection at the pumps themselves. (not uncommon to have the hose come off, after all these years!)

No need to get into a dissertation on "next steps" now, especially since you have the FSM. The troubleshooting charts will walk you through the rest of the fuel delivery, for the most part. Let's see what develops - would be my approach...

[RussMcB]

Thank you, Paul. Sounds like a good plan. I'll report back with what I find.

[mike100]

That said, the fan running is a sign that the ecm is in a weird state- like the diagnostic mode when you plug in the tech1 scanner or like when you plug the chip in backwards on the ecm.

[RussMcB]

Originally Posted by mike100

That said, the fan running is a sign that the ecm is in a weird state- like the diagnostic mode when you plug in the tech1 scanner or like when you plug the chip in backwards on the ecm.

Thanks, Mike. I sent an email to Marc Haibeck last night and he replied with similar thoughts, like maybe it had gone into limp home mode. Marc suggested I check the chip to make sure it is seated correctly. I'll do that when I get to the garage tonight. I've also disconnected the battery and will reconnect it tonight.

[RussMcB]

Problem solved!

Big thanks to Marc (and Mike) for pointing me in the right direction. Apparently, my chip was not fully seated. I removed it, reinserted being careful everything was square, and the car started right up.

I also discovered my fuel pressure tester (or hose, fittings) must be broken because it continued to read zero pressure with the engine running.

Now I'm wondering if there is anything I can or should do to prevent it from coming loose again. The little blue and white clips were snapped in place correctly (I think).

Thanks, ZR-1.net !

[We Gone]

I would think your good to go on the prom now, sounds like it just was not seated correctly the first time.