87 reliant start and immediately stalls
Well I went through the usual diagnostic tests but I’m stuck on this one. 87 reliant 2.2 TBI automatic. I’ve been daily driving this for work the last couple months because of diesel prices, so I don’t want to drive the truck back and forth at $6.50 a gallon. Left for work last night and made it only 2 blocks from the house before it stalled at the stop sign. No time to mess with it, so I walked back home jumped in the truck and went to work.
Earlier today I went back down with some tools and started messing with it. Fuel pump primes, it’ll fire for a second, then stalls. Will not fire again unless you let it sit a while.
I pulled the regulator and there’s fuel there. Briefly cycled the key and it’s pumping fuel no problem. Ohm’d the injector coil and it’s 1.4-1.5 ohms. Jumped 12 voltsdirect to the coil and it clicks and you can see it spray down the throttle body. Then probed the injector connector and cranked it. It was bouncing around (as I would expect it to since I would imagine it runs a PWM signal) but was in the neighborhood of 1.5-2 volts. Car will start on ether and continue to run if you keep feeding it ether.
only thing I can think is I’m not getting an accurate reading on the voltage going to the injector using the normal DMM. Any suggestions are appreciated!
Re: 87 reliant start and immediately stalls
hall effect pickup? they are known to go bad.
map sensor signal wire volts with key on engine off?
could be a number of things.
Logic module in the kick panel full of ants? black and clearish connectors corroded?
connections at the power module corroded?
12v on one side of the coil, and one side of the injector when the fuel pump primes?
shouldnt be too hard to diagnose. they are pretty simple. not GM HEI and a carburetor simple but not too far off.
Brian
Re: 87 reliant start and immediately stalls
Quote:
Originally Posted by
Aries_Turbo
hall effect pickup? they are known to go bad.
map sensor signal wire volts with key on engine off?
could be a number of things.
Logic module in the kick panel full of ants? black and clearish connectors corroded?
connections at the power module corroded?
12v on one side of the coil, and one side of the injector when the fuel pump primes?
shouldnt be too hard to diagnose. they are pretty simple. not GM HEI and a carburetor simple but not too far off.
Brian
I was thinking not the pickup since it’ll stay running with ether so it has ignition. I haven’t checked the LM yet but will tomorrow. What would be needed to test the wire at the injector directly. I assume a meter that can measure duty cycle? Didn’t check the MAP voltage I assumed they’re totally different circuits as they come out of the ecu
Re: 87 reliant start and immediately stalls
stalled at stopsign...
was your foot on the brake?
a leaking booster will stall you out when you step on the brakes
stalling when coming to a stop could well be the speed sensor too.. it's a common fail when they go
booster is easy to check ..disconnect the vacuum hose to the booster and plug it with a bolt..see if stalling ceases
Re: 87 reliant start and immediately stalls
MAP sensor is where I would start.
Unplug it and see if car continues to run and not stall. The ECU will use "substitute values" to keep running once the sensor is out of range (unplugged)
Gary
Re: 87 reliant start and immediately stalls
Thank you guys! I’m leaning toward the MAP as well. Was going to ask if I could simply unplug it and get it home via limp mode. I thought I remember being able to do that with other TD’s in the past and just get a 13 or 14.
Re: 87 reliant start and immediately stalls
At the vehicle now. No change whether MAP is plugged in or not. Voltage at injector connector is 3.xx at prime cycle, between 1.5 to 2.5 during cranking. This is probing positive wire of connector and negative probe of meter directly on ground of battery.
Re: 87 reliant start and immediately stalls
We need some more direction. What is missing that is causing it to stall:
If you give the engine some throttle on startup does it stay running... if so IAC issue.
If you spray some starter fluid and it stays running longer, then a fuel issue.
If you have a spark tester or a test light you can confirm spark continuing.
Note that this is just direction, not the solution. ie. fuel issue could be fuel injector, computer, wiring, fuel pump, etc.
Re: 87 reliant start and immediately stalls
start with the last thing you did with the car
you slowed down and stopped...and stalled
brake booster stalls while braking
speed sensor stalls once stopped ..and often throws no code
Quote:
Originally Posted by
Dr. Johny Dodge
stalled at stopsign...
was your foot on the brake?
a leaking booster will stall you out when you step on the brakes
stalling when coming to a stop could well be the speed sensor too.. it's a common fail when they go
booster is easy to check ..disconnect the vacuum hose to the booster and plug it with a bolt..see if stalling ceases
- - - Updated - - -
start with the last thing you did with the car
you slowed down and stopped...and stalled
brake booster stalls while braking
speed sensor stalls once stopped ..and often throws no code
Re: 87 reliant start and immediately stalls
Thanks for the advice guys. It would seem it’s narrowed down to a voltage to the injector issue. It will start with starting fluid and continue to run if you keep feeding the ether in the TB. It did stall while hitting the brake but that could be coincidental. Using the ASD jumper technique there is voltage at the positive terminal of the coil but not at the injector harness. I’m trying to back probe the 10 pin on the PM to see if I have the voltage there I’m supposed to have.
I drove the car the night before it had this issue and drive it a few times a week about 20 miles round trip. If power is jumped to the injector it sprays after pump primes to build pressure. If you manage to start it with ether it does not stay running no matter what you do with the throttle. I’ve confirmed injector is not spraying
Re: 87 reliant start and immediately stalls
I believe that since these are low-impedance injectors that should have a peak and hold waveform. You will need a scope to see if the pattern is correct. Decent chance the injector drivers are fried... still could be a wiring harness or connector issue too.
Re: 87 reliant start and immediately stalls
Quote:
Originally Posted by
c2xejk
I believe that since these are low-impedance injectors that should have a peak and hold waveform. You will need a scope to see if the pattern is correct. Decent chance the injector drivers are fried... still could be a wiring harness or connector issue too.
to be honest I’m not sure if the TBI injector is low or high impedance, but I know the power is supposed to be constant 12 volt and the PW is controlled by the switching of the ground leg. I’m not getting voltage to the injector at all at this point and that’s with my ground clamp direct to the battery
Re: 87 reliant start and immediately stalls
Going by memory sitting in Chrysler dealer training, early TBI had switched positive at injector, and in 1988 all changed to toggled ground side.??? and my memory isnt that good.
And it should be a .95 ohm injector. Had many problems with that injector. Changed many of them under campaign 97 warranty recall.
Re: 87 reliant start and immediately stalls
Quote:
Originally Posted by
Warren Stramer
Going by memory sitting in Chrysler dealer training, early TBI had switched positive at injector, and in 1988 all changed to toggled ground side.??? and my memory isnt that good.
And it should be a .95 ohm injector. Had many problems with that injector. Changed many of them under campaign 97 warranty recall.
The TBI injectors are known to be junky, changed many, many, many of them out.
Re: 87 reliant start and immediately stalls
Can anyone confirm if in 87 the injector is being fired by switching the positive or the ground? I’m definitely not getting voltage at the injector harness so if it’s supposed to be just switching ground I have another issue. If it is supposed to switch power I could still have an issue further back, perhaps an input to the LM or the LM itself
Re: 87 reliant start and immediately stalls
Quote:
Originally Posted by
TIIIReliant
Can anyone confirm if in 87 the injector is being fired by switching the positive or the ground? I’m definitely not getting voltage at the injector harness so if it’s supposed to be just switching ground I have another issue. If it is supposed to switch power I could still have an issue further back, perhaps an input to the LM or the LM itself
Yes, If your 87 does not have SMEC, and uses the logic module/power module; then the injector is pulsed by the power module on the positive side. The injector was provided a constant ground on the WT wire; and when the inj. was turned on, the power module would supply 12V on the TN wire.
Also, the TBI's did not use an injector driver. Rather, they used a complicated circuit (comparator network)to supply 12 volts to the injector. The results are the same, but the methods were different.
I verified what I remembered by looking back in my old Chrysler drivability workbook. I even wrote a note about it in my workbook.
The as installed injector had a black body. The warranty injector had a red body. .95 ohms.
Re: 87 reliant start and immediately stalls
Quote:
Originally Posted by
Warren Stramer
Yes, If your 87 does not have SMEC, and uses the logic module/power module; then the injector is pulsed by the power module on the positive side. The injector was provided a constant ground on the WT wire; and when the inj. was turned on, the power module would supply 12V on the TN wire.
Also, the TBI's did not use an injector driver. Rather, they used a complicated circuit (comparator network)to supply 12 volts to the injector. The results are the same, but the methods were different.
I verified what I remembered by looking back in my old Chrysler drivability workbook. I even wrote a note about it in my workbook.
The as installed injector had a black body. The warranty injector had a red body. .95 ohms.
very good to know! NAJ on the other forum floated that it could be pulsed by the power side but couldn’t remember with any certainty. That would at least explain why I’m not getting constant 12 volts as one would expect with MPFI. Thanks!
