cutting off (no codes)

[spiro440]

I will try to be as complete as I can.
I just performed a complete engine swap(harness,relays,etc...) from the firewall to the grill for my omni GLH.
The complete swap came from another GLH that was smashed by the rear while being parked. The car ran perfectly the swap.
The car had the 1989 turbo II set up with a stage 2 computer from Mopar and some head work.
The car ran good for a 100 miles or so after the switch. Everything seemed tight. That's when I decided to go for a real run. After a few drag type lauches the car died. No spark! Started ten minutes after and died 5 minutes later.
Changed the pick up coil (took from my turbo mini)and fired right up. never stalled again but missfires (and backfires once in a while). Idles good.I can drive around town but can't open it up??
And it is difficult to start when hot.
- Changed distributor cap and rotor
- Changed plugs and wires
- Checked for vacuum leaks
- Changed injector harness
- Added two extra grounds
- Checked timing
- Checked timing belt
- Installed fuel pressure gage( pressure good and stable)

The car had a S-60 set up that ran good before swap
Any ideas??
Thanks

[chilort]

1) not likely, but vapor lock
2) LM going bad and occasionally not providing the distributor signal
3) bad HEP

[spiro440]

Quote:

Originally Posted by chilort 1) not likely, but vapor lock 2) LM going bad and occasionally not providing the distributor signal 3) bad HEP

It has a SMEC, wouldn't it give me a some kind of code?
The HEP is a knew one that I had put in my mini van and removed it to put in the Omni. Would I be that unlucky. I Just put another one in the van. Should I swap again???
Vapor lock?? some times if I go easy on the throttle(in 4th or 5th) I can get it to 14lbs boost and 5000rpm and then it starts acting up.
??????

[NAJ]

Need a few questions answered.
Unfortunatly a vehicle that has a driveability concern like yours without setting fault codes requires diagnosing each system seperatly and eliminating that system as the cause. Do not overlook anything or assume it is correct or you may jump right past the problem. Also in order to properly help we need numbers and more detailed info so....
1) Does it backfire thru the intake or the exhaust?
Be absolutly positive that cam timing is correct, 1 tooth off will create all types of problems. I am sure you already know that the Cam is aligned 12 o'clock with the centerline of the head not 12 o'clock straight up and down.
Is belt tension correct?
2)What are the fuel pressure numbers? Connect your gauge and tape it to the windshield and drive the vehicle under the problem conditions, what is your rail pressure and what is the vacuum/boost reading, you need both to determine total pressure across the injectors. (that is how mpfi works)
Static pressure is 53-57 psi, you will lose 1psi of rail pressure for every 2"hg applied to the fpr and rail pressure should increase 1psi for each lb of boost.
Get the car hot, shut it down, watch the pressure, is it holding or did it suddenly drop?
Now crank the engine in your" hot hard to start condition" what is rail pressure reading?
3) What is engine vacuum at a manifold source at idle? Are you reading the same at the baro solenoid? Are you reading the same between the baro and map sensor?
Is map voltage reading = to vacuum/pressure?
(voltage charts can be found in the "sticky", voltage tables.)
Tee a vacuum gauge between the baro and map and drive under your problem conditions, is map vacuum/pressure correct?
4) Be sure there are no exhaust restrictions, remove the O2 sensor, leave it plugged in and secure it out of the way, drive the vehicle, is the problem gone? Removing the O2 sensor will relieve any excess backpressure.
5) If all of the above check out you need to start looking at low ignition output as being the cause such as a faulty ignition coil.
FYI, If you lose the crank signal from the HEP it will not set a fault, only if it loses the fuel sync signal.
When the car will not restart hot what do you have to do to get it started?
If it just cranks and cranks and all of the above(fuel pressure, etc) are ok check for power at the + coil while cranking, is power present? If not the problem lies in the ASD relay or HEP circuit.
You may also want to perform a "wiggle test" on all the wiring/connectors while the engine is running, pull/tug/twist on the harness's and connectors at the sensors/controller/harness connectors to isolate a faulty connection.
That should keep you busy for a while, LOL, let us know the results and we will go from there.
In my perfect world we would all have access to a dyno, oscilloscope, scan tools and gauges so we could run the car under the problem conditions and monitor all the systems at once.

[spiro440]

I finally did your list:
1) backfires throught exaust. Timming is correct(Cam as well)
2)47 psi at 16 hg, 60 psi at 5lbs. Pressure holds when shut off.
3)16 Hg at idle. Same at baro and between map. Voltage 0.1 at baro.(did not take it at map.DOH!! Don't make me go back. lol!!)
4)Removed complete exaust(neibours loved me)no change,but overboosted once.
5)Car will finish by starting when just shut off and restarted. When cold, starts right up.Did the wiggle thing, the twist and tug thing and all the other slapping ,knocking moves I could possibly think of on every wire, connector I could possibly see. Removed inspected the pins and reinstalled the Smec.

Whent to my buddy and plug the DRBII. Did all the test and nothing. Drive test, nothing!
Does the probleme and the drbII seeeees nothiiiing!!!!

[NAJ]

Backfires thru the exhaust either means rich or incomplete combustion, sounds like a secondary ignition problem. Coil? Coil Wire? Cracked Distributor Cap? Arcing or High Resistance Ignition Wire. Plug Problem, Cracked Insulator, Wrong Gap, Deposits.

[85boostbox]

you guys might be looking to into it. hard start when hot, popping through the exhaust. sounds like the coolant temp sensor at the thermostat housing. when you did the engine swap did you follow the timing instructions.
8) Distributor timing procedure not followed.

Seen this more then a few times- The Coolant Sensor Must Be Unplugged! It's the sensor to the right of the thermostat right in front of number four sparkplug.

A) Start car, run till normal temp.
B) Unplug coolant sensor, cooling fan WILL turn on.
C) Set timing to 12 degrees, lock down distributor.
D) Shut car off, plug sensor back in- On 84-87 vehicles disconnect battery to reset computer.

Simple no? If your mechanic cannot follow this procedure, find another one or do it yourself.
would be better if you just bought a new one anyways just to be safe. there like 20 bucks maybe. try that and let me know what goes on.
P.S. I've seen coolant temp sensors not throw codes

[spiro440]

Checked the timming with the sensor unplugged. Even wen't to borrow another timming light just in case mine was defective.Rechecked the timming belt. Asked a friend(Chrysler mech. and owner of the donner car)to double check with out me around.Everything in the ignition systeme is new. I took a break from the car this week.
I will get on it tomorrow,and start fresh.

[spiro440]

Got back on it.
redid all the checks, swaped parts from my minivan to isolate the probleme again.Reswitched the HEP and .....IT WORKS?????
Can`t figure it out. It`s the third one.Put that one on the mini and it works fine?
BIG THANKS for your help. Now I only got to fix an exaust leak. After all those backfires something had to give in.
Spiro