Need help from chevy experts, new towed not working

[orfunauto/Darrell]

 I just picked up a future towed, an 86 S-10 with a 2.5 TBI. It has been sitting (about a year) since some one diagnosed a noise in the engine when cranking as a bad main bearing. It was a bad starter..... But I still have a problem. I can not get an injector pulse. It will fire if I run a test wire to the purple/white wire coming out of the distributor, so the injector is not plugged. The engine will run fine if fuel is pored into the throttle body, so the ignition is working properly. I checked the quad drivers as per the snap-on guide, and they have .18 and .09 ohms resistance, which is within the parameters per the guide. What's next?


removed OT: Richard

[jackhartjr]

I guess my question is why is this in the OT forum?
Being that it is a toad, I would think that it should go in the regualr forum?
Jack

[DrivingMissLazy]

I guess my question is why is this in the OT forum?
Being that it is a toad, I would think that it should go in the regualr forum?
Jack

Jack, the moderators look for these kind of things and try and move them to the proper location. I generally move any OT: items from the main board to the OT: board after they get to the second page. This was by Nicks instructions initially. Since the OT: has became so popular, I suspect we could go ahead and move them as soon as they are discovered. Nick and I have moved several posts from the Help board to the main board and I will go ahead and move this one.

Richard

[jackhartjr]

Thanks Richard, it just seemed to be a problem that someone on the board here could answer quickly.  I don't go over to the OT board a lot...and I think a lot of folks probably don't either.
Thanks again, maybe this guy can get some quick help.
Jack

[NJT5047]

Darrell, since the engine (starter...reason enough?  )has infarcted, pull the engine out and drop a 4.3 in there.  MUCH better engine.  There are cheap donors all over for that application.  2.5s are problem engines...especially those TBI units. 
OR, install a carb on it.  Some came with carbs.  North Carolina won't emissions test  OBD1 and down.   
Is this a 4WD?  I've never seen a 2.5 in a 4WD?  Do you plan on towing 4 down? 
Sorry that none of this answers your question.   
GM TBIs picked up a position sensor from the distributor.  #1 and #2 injectors are hot in run and start position.  (believe red and white leads).  Check for 12V input at both injectors. If you have that, check for broken leads on Dk Blue or Lt Blue and Drk Green or Lt Green ECM leads.  These leads ground the injectors thru the ECM.  Broken leads, bad plugs, etc will cause same. 
There are two Purple/White leads.  One powers the ECM in "start" position, the other is a distributor to ECM lead.   
Since it runs when fuel is poured into the intake, the distributor is probably working.  I'm assuming no CELs are set?  If so, download the codes.   If no codes are set...=>
Check the injector leads from the ECM/Ign fuse for power in the run AND start position.  Could be a ignition switch problem (purple/white wire to ECM.  And injector power leads.). Resist the urge to "jump" 12V to any leads.  This isn't a good idea.  And remember that there are two, unrelated Purple/White leads on the engine.     
Power goes from the ECM/Ign fuse to Dk Blue/Lt Blue and Drk Green/Lt Green (various models used the Dark or Light coloration).  Ign "On" and "Start" should also power up the Pink/Black lead at the ECM.  Probe these for 12V when key is on and start.   Grounding the Dk Blue or Dk Grn leads should cause the injectors to pulse.  If not, the truck may have set so long that the fuel has gelled in the injectors and they are locked up.  If so, it wouldn't start, no engine codes would be set, and everything would work...just no fuel injected.  You can see the fuel inject if you ground the Dk Blue or Dark Green injector leads.   
A WORD of Caution...turn the ignition switch OFF, and disconnect the ECM before grounding any leads that are connected to the ECM.   DO not ground the Pink/Black wire.  That's an ECM switched power lead.
At some point you'll need to verify that fuel pressure is suitable...and that the fuel pump is running.
You should be able to hear the injectors click when ground the ECM leads.   Seized injectors would be my best guess.  Since it runs with a splash of fuel. 
I know that you are fire concious....squirting fuel injectors makes the perfect fuel air ratio for a fire. 
If you find that the injectors are working and injecting fuel, you may have an ISC or EGR stuck and it's allowing too much air to flow through the wrong holes.  The "wrong hole" thing is always a bummer!   
Back to the transmission...unless the truck is a 4X4, feel free to correct me on this, it cannot be towed 4 down.  Chevy didn't recommend towing a manual trans in neutral.  The input/main shaft bearing cannot  handle the lack of lube at highway speeds without the input shaft turning (typically at  1-1 in high gear).   
I installed an NP231 in my AWD Astro Van (the one with the LT4) so that I could tow the thing.   I haven't.  Have a nice Jeep that I do tow...rarely.  But that is the only mechanical transfer case that is towable in S10s, Astros, and S10 Blazers. 
More research is in order!   Now if you are going to trailer it, or back onto a dolly, no problemo.
Let me know what you find.  That electrical system is pretty simple.  You may have a bad ECM, but I doubt it.  Same for the dist.  If it runs, those items are working. 
You'll probably have to replace the O2 sensor after this exercise.  If it idles ratty, I'd recommend replacing the EGR valve too.  They get old and become leaky...creating a bad idle..poor driveability.   The EGR is necessary to prevent pre-ignition.  The early ECMS didn't have anti-knock sensors. 
Let me know if you need more wiring IDs.  I probably have something that will give what you need. I've got a collection of Astro/S10 and 9C1 Impala from the engine exchange thing. 
HTH! JR

[Darrell]

Thanks for the great answer JR.  I did field test the injector firing by running a test light through the purple/white wire comming out of the distributor.  The new injector fired perfectly, so I'm assuming the fuel pressure is good.  Is there a hall effect switch in the distributor on this year model?  I've got a feeling that because the truck sat for so long, that there's a possibility that there may be corrosion on the pick up/reluctor inside the distributor.  I'll check that tonight when I get home from work. 

I bought this truck to tow four down.  I also bought another identical stretch cab truck which has a five speed, but a poor body.  Eventually I'll swap out the transmissions and have myself a nice towed.  I also have a 4.3 sitting in my shop that might just have to replace the 2.5 with while replacing the transmission.....

P.S.  Thanks for putting this post in the right forum.  With all the controversy about correctness in posting, I didn't know for sure where I should put it.

[NJT5047]

I'll check on the distributor.
Regarding the transmission, I'm of the impression that a 2.5 trans won't interchange with a 4.3 transmission.  Different bell housing.   If the bell housings can be interchanged...may work.   4.3 is a much better package.  Good power and the later 4.3s are smooth. 
Check for the trans interchange before going down that road!
The automatics will not interchange.  That's all I've dinked with.  4.3 has V8 bolt pattern...2.5 has proprietary bell housing bolt pattern. 
Have you taken a 12V test light, attach the ground clip to the postive battery terminal, and stick the test light probe into the plug that grounds one of  the injectors.  Turn the engine over and it should pulse.  If it does, the distributor is working.  If not, either ECM or distributor could have issues. 

Later, JR

[orfunauto/Darrell]

Thanks again JR. 
I did check for an injector pulse using the purple/white wire coming out of the distributor.  It fired just like it should.  After talking with a Chevy mechanic today, I pulled the hall effect switch out of the distributor tonight.  I'll pick up a new one tomorrow.  I was hesitant on pointing my finger at the switch yesterday since it's a $70.00+ non-returnable part.  But after talking with you and the local fellow here, I'm going to bite the bullet....  I'll let you know how it comes out tomorrow evening.

Darrell   

[NJT5047]

I'll bet something of low value that the HE doesn't fix the problem.   The purple wire from the distributor is between the distributor and the ECM.  The fact that it runs likely indicates that the distributor is good.  The same signal informs the ECM when to fire, also advises it when to inject.  If the TPS is working.  I'd look for a donor in a junkyard.   
The TPS could cause the non-injecting condition.  They will get intermittant..run a little then quit.  After a while the TPS gives up. 
I notice that your engine does have knock sensors....I incorrectly state that it didn't. 
Have you checked the ECM Purple/White wire that is supposed to be "hot" in start position?  That is a fused lead and may cause your problem.  This isn't the Purple/White dist lead.   
Do you have access to an OBD1 scan tool?   If you have a component failure, that will generally locate the problem.  Not always, but it'll get you on track. 
Another thingy, be sure that the fuel pump runs when the ignition switch is turned on.  Fuel pump faults are a common problem on GM products.    It should run for 6 to 10 seconds every time the key switch is turned to the "run" position.   I would expect the fuel pressure to be around 40 lbs. 
Generally, the unit defaults into a limp mode and will run with almost all the sensors disconnected.  The TPS, fuel pump, and blown fuses, distributor will stop the engine from running.  Fuel pump and pressure faults will not be sensed by a scan tool.  If no CEL, probably no electrical problem.     
If the injectors are pulsing when a test light is stuck into the Drk Green ECM pin, the system is working.  The problem is fuel supply.  Couldn't be any water in the fuel?? 
That's my tip of the day.  Be sure that the fuel pump is running and verify that the fuel pressure is WNL.   
Waiting to see if the dist repair is the fix.  I may owe you a "cold one" if the distributor repairs the problem!  Good luck!
JR 

[Darrell]

I ran a fuel pressure test last night just for grins.  Have 14#'s at the throttle body.  System requires 8 to 15#'s to operate.  40#'s are required to run port fuel injection, but not throttle body.  The purple/white wire coming from the distributor is the pulse reference wire that sends a pulse signal from the hall effect switch to the computer, which in turn pulses the injector.  When you hook a test light to the positive side of the battery and pierce the purple/white wire, it sends that positive signal to the computer, and the computer fires the injector.  Because I had sucess in that test, it has told me that I have good fuel pressure, good wiring to the computer, and a good computer signal to the injector.  Test procedures were followed directly from the Snap-on scanner reference book that came with my hand held scanner.  The scanner also told me that there are no codes set, but that may be due to the battery being dead for so long.  I'll let you know tonight if I blew that seventy+ bucks or not......    

[NJT5047]

My ADHD OCD personality requires that I must know NOW Now NOW!!!   
Hope your $70 bucks fixes it! 
Regarding the fuel pressure...I'll go for 14 lbs.  I'm getting my info from an Astro Van manual...there were a few 2.5s apparently installed in some work trucks.  Not a good source...better than nothing!   
JR

[orfunauto/Darrell]

That did it!  Replaced the hall effect switch and it fired right up.  But after running a few minutes, I got a service soon light.  Hooked the hand held back up and found two codes set.  22 - TPS out of adjustment with low signal, and 42 - electronic spark timing (EST) problem.  Should be minor problems.  Probably an adjustment for TPS, and hopefully, a wire for the EST.

Thanks for the support JR.  I'll post the repairs for the two codes as they are solved.

We're taking the coach up to Mt. Airy for a short trip Friday to Sunday.  Antiquing     for my other half, but will stop on the way back at the state fairgrounds for a car show/swap meet on Sunday for my pleasure...

[NJT5047]

Glad to hear you got it running!     I don't understand (story of my life~) why no trouble code was set by the position sensor?  Would'a thought it would have a failure code.
At least with the CELs you can finish the job now.   Then get on with installing a small V8 or the 4.3.   
When you go out in the bus this weekend, take your drop cord for the block heater!  Gonna get cold. 
We'll be in Mt. Airy next June...first weekend, at Veteran's Park for a festival.   Not going to be much bus'n going on during cold weather.   
Cheers, JR