Engine removed/replaced, has spark, fuel, timing, no start...

Canndspam · Feb 6, 2013

So I just pulled my engine, ('86 2.9 2wd) replaced nearly all the gaskets (heads, lower intake mani, oil pan, timing cover, water pump, front and rear main seals, valve covers) as most were leaking. Put it back in, hooked it all up, cranked it, it started up, ran rough for about 6 seconds then died, ne'er to start again. It'll crank but won't kick at all.
-there's pressure in the fuel rail
-there's spark at the coil and each of the plugs
-checked the block for ground with a multimeter
-the distributor is not 180'ed (checked for compression on #1 on the way to tdc)
-plug wires are going where theyre supposed to
-tried some starting fluid but got nothing while cranking, not even a pop
-i didnt touch the timing chain or any block internals while it was out and the timing marks were aligned when i replaced the front cover.
-ran the codes and it threw 21 and 24 (air charge and engine coolant temp.) but i dont think that should prevent starting.

It seems like a spark issue because of the lack of ignition with the starting fluid but I don't understand why when I pull the plugs and ground the threads I get good hot spark.
Wtffff am I missing here? Any and all ideas are appreciated!

cammeddrz · Feb 6, 2013

is there an injector sinal? go to Oreilly, and get a $9.00 "noid" light, and hook it up to the injector connector, it will tell you if the injectors are getting the signal to pulse

Canndspam · Feb 6, 2013

I haven't tested the injectors directly but while cranking, the exhaust smells strongly of gas and when I've pulled the plugs they've also smelled like gas so it does seem like its getting fuel. Could it be getting too much?

cammeddrz · Feb 6, 2013

what is your fuel rail pressure?

ericthedean · Feb 6, 2013

check ohms in the coil you mabe getting spark but not strong also are the plugs getting fuel fouled

Tedybear · Feb 6, 2013

ericthedean said:
check ohms in the coil you mabe getting spark but not strong also are the plugs getting fuel fouled

Strong possible here. We just went through this with our BII 2.9. Had spark at the plugs when out of the engine, but I feel that when installed? The spark wasn't enough to do the job (compression raises the voltage needed to 'spark')

Do you have a spare coil to test with? For what it's worth? Ours tests "Good" according to the meter---but I think there is a hairline crack in the plastic that is hiding an arc we can't see somewhere around the core. I put my hand next to it in order to wiggle the wires..and got nailed 2" away from the coil.

not saying this is it? But it's a starting place.

S-

CarsonChris · Feb 7, 2013

Check your grounds

RonD · Feb 7, 2013

Spray can of Engine Starting fluid will narrow down your search for the problem.
Spray it in the intake
Turn over engine, if it fires and dies then fuel is your problem
If it doesn't fire then Spark is the problem, but fuel is not off the table, you just need to get the spark working first.

I would pull a few plugs to see their condition first

Canndspam · Feb 7, 2013

Ok so...

In the process of testing I blew up the starter. Replaced it and the battery terminals and had the battery checked and tested the solenoid. Back to cranking again.

Fuel pressure at the rail is 38psi with key on, 40 when cranking.

I switched out the coil with a brand new one and it had no effect. still a blueish orange spark when grounded to the block.

Tried starter fluid again with the new coil. Still no kicks.

Sanded and dielectric greased the grounds between the block and battery, between the battery and frame and the coil ground.

When I pulled one of the plugs after cranking it seemed to be wet with gas.

The guy at the a/z told me that i couldnt use a noid light on my truck to test the injectors. I dont know enough about the matter to say he's wrong but... I'm planning on getting my hands on a stethoscope tomorrow so i think that should serve the same purpose.

On a random thought, I disconnected the fuel injector plug and sprayed some starting fluid and it cranked at much higher rate and almost seemed like it kicked a couple times though it was hard to tell. Could something be causing the injectors to just stay open or to put out enough fuel to flood it? Could the dead air charge and ECT sensors be messing with it enough to cause that?

Thanks for all the help gang.

RonD · Feb 8, 2013

Unplug all the injectors and just try Starting Fluid into the intake, that should tell you if the injectors/PCM are the problem.

The injectors will have 12vDC on one wire when key is on, the other wire is the ground.
The PCM(computer) grounds the injector to open it.
You can test for 12vDC only at the injector, the ground shouldn't be grounded if you want to test OHMs on that wire

A weak spark could be an issue or improper gaps.

If you have a timing light can you check #1 and TDC, while someone else cranks the engine.
Are the distributor plug wires in the right positions, not just firing order, when engine is at TDC rotor is on #1 in cap.

Check the fuel regulator's vacuum line for gas, if the diaphragm leaks raw fuel gets sucked into the intake

Canndspam · Feb 8, 2013

I pulled one of the injector plugs off the injectors and tested both prongs with the key on and they both were showing a little over 12V. Neither one appeared to be the ground. I went back one connector further to the plug that connects to all 6 of the injectors and tested the three prongs in that connector and two of them had no voltage and were grounded and one had a little over 12V. Does this mean that something in the PCM is shot? I replaced it less than a year ago. My understanding of these electronics is not spectacular.

Also, the plugs are gapped properly, when the crank is at tdc the rotor in the dist. is at the #1 column, and i didn't find any fuel in the vacuum line off the regulator.

RonD · Feb 8, 2013

If you go here:
http://www.therangerstation.com/tech_library/EDiagrams/index.htm

And look at 2.9 engine page "3 of 3" engine controls, you will see the wiring diagram for the injectors, it looks like they only use 2 grounds from the PCM/EEC, so fires 3 injectors at the same time.

Power wire "361" comes from Page "1 of 3"

I would still unhook all injector wires and try the starting fluid, if it fires then you will know the issue is at the injectors or PCM

Canndspam · Feb 13, 2013

So I finally got it running and I thought I would post my findings.

I had a combination of weak and intermittent spark and over fueling. The ignition coil was the source of the weak spark, the distributor cap was responsible for the intermittent. When I would pull a plug and ground it to the block, it appeared to be firing fine but when I finally put a proper spark plug tester to it it showed up for what it was. So I replaced those and it ran til it started to warm up, then it died. I pulled the codes and it was throwing 51 and 54, ECT/ACT indicates -40/circuit open, respectively. In this time period I also learned that the body of O2 has to be clean, and it was covered in oil from the massive oil leak that had sent me on this endeavor in the first place. All three of these sensors were basically telling the computer to dump fuel into the engine with reckless abandon. So I replaced the ECT and ACT and cleaned off the O2 and all seems to be well. Holy cow.

RonD · Feb 13, 2013

Thanks for posting the findings and fixes :icon_thumby:

Tedybear · Feb 13, 2013

Canndspam said:
So I finally got it running and I thought I would post my findings.

I had a combination of weak and intermittent spark and over fueling. The ignition coil was the source of the weak spark, the distributor cap was responsible for the intermittent. When I would pull a plug and ground it to the block, it appeared to be firing fine but when I finally put a proper spark plug tester to it it showed up for what it was. So I replaced those and it ran til it started to warm up, then it died. I pulled the codes and it was throwing 51 and 54, ECT/ACT indicates -40/circuit open, respectively. In this time period I also learned that the body of O2 has to be clean, and it was covered in oil from the massive oil leak that had sent me on this endeavor in the first place. All three of these sensors were basically telling the computer to dump fuel into the engine with reckless abandon. So I replaced the ECT and ACT and cleaned off the O2 and all seems to be well. Holy cow.

Oddly enough? That's the same issue I had with our BII not starting.

I'm very glad you worked this one out and let us know what was going on. Sounds like you did a great job of troubleshooting this one! Well Done!!

S-

Engine removed/replaced, has spark, fuel, timing, no start...

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