4.0 swap and no start

[CheapThrillEX]

took 90 ranger with 2.9 and m5ord

put in a 91 explorer 4.0L entire engine comparntment harness and everything from behind dash, did the whole elec swap, it all worked before i touched it

bypassed the nuetral safety on auto harness

engine cranks just fine

but i have no spark and no inj pulse when checking with noid light, have good fuel pressure

the three relays click like their working

i've rechecked all connections and grounds and etc....

the only thing not hooked up is the o2 sensor

 

[Rick]

I'm going to move this to our Under the Hood forum. You should get more views there.

Sorry I can't help you with this one.

 

[410Fortune]

Have you checked for 12v+ at the red wire on an injector?
The pulse to the injectors as you know is a ground signal from the computer and they should have 12V+ from the computer acc+ when the key is on.

Did this 4.0L ever run? You said it worked before you touched it? Or is this the first attempt to start it?

since the starter is cranking with the key this is not a NSS issue

 

[CheapThrillEX]

i drove the explorer into the garage to take out the 4.0L.....

i did check for voltage at the coil with KOEO and at the Relays near the blower motor...all seemed good, tomorrow i'm gonna try a different ICM

 

[CheapThrillEX]

i have battery voltage at the injectors (both wires)
i have 1.5 volts at the crank sensor
power is supplied to the ICM on core support and has good grd

still no flash at injectors with noid light and no spark

it hasn't run since being installed in the ranger
i didn't have another ICM to try

 

[410Fortune]

okay so when you put the 91 engine into the 90 ranger did you just plug inthe big white firewall plug or did you check the pinout from the engine/computer harness to the truck??

I think some wires changes locations but I am not sure, funny thing is every 4.0L conversion I have done were pre 89 without the big white plug, but I have read a few of them online over the years.

These kinds of problems can be very hard to figure out, but it sounds like you are very close, you just have a no spark situation and I am not sure why

 

[CheapThrillEX]

tried a known good ecm and icm, still nothing, now i am official stumped

yeah no spark and no flash at injectors...

i changed all the dash wiring to...pulled both dash's out and swapped that harness as well....i went this route so it "would have been easier" then splicing wires

 

[410Fortune]

check the EEC relay and fuse, make sure they are powered up
( I am guessing it is since you have 12V+ at the red power distribution with the key on)

How is your ignition module? is it hooked up to the wiring harness?

I am just thinkingout loud here

Dammit I wish I could travel to physically look at all these conversions, it is so damn frustrating to do all that work then have something not work and spend forever trying to figure it out.

One conversion we did we hadth efuel lines backwards, even though we checked them about 8 times it took us 4 days to finally realize they were indeeed backwards.

The other time this happened was a 5.0L HO conversion and we were getting no power at any sensors, the custom wiring harness we built, well we missed one splice, took a couple of weeks to figure that one out, and about 12 minutes to repair.

 

[410Fortune]

are you running the automatic computer with a 5 speed?
just curious

 

[CheapThrillEX]

yeah it has the autocomputer with the 5spd in the truck....we have this same combo on a explorer we run with and no probs yet...

yeah i plugged the icm in and even tried a known good one....its gotta be something simple and stupid...i wanna figure this out today....but tomorrow when i go back to work i can use Alldata and use the pinpoint tests to figure it out...all i got here today is a crappy hanyes manual

 

[410Fortune]

a pinout box would help a great deal.

check the timing pil

check the ingition module plug

check all plugs at the coil pack, in fact you can check that the coils are getting power, it could be a bad coil pack?? I know it worked before but stranger things have happened.

you already checked the crank sensor, seems everything is fine there, but dont overlook th ewiring and pins to it, as I understand it th ecrank sensor is responsible for a no spark condition often

 

[CheapThrillEX]

i'm pretty much convinced its gotta be a ground problem.....no check engine light on with KOEO...gonna go through and recheck all grounds and clean them

 

[410Fortune]

dont forget the grounds near the computer and the ground wire that goes from the frame to the engine block back by the oil filter mount.

 

[CheapThrillEX]

thanks for all the help.....i spent several hours chasing wires doing diag on components etc.....busted out the breakout box and started checking things and was just messing around confused. And without really doing anything, just screwing around tried to start it and it started and has kept starting since then, runs fine, idles good, who the hell knows but it starts and runs so it can leave my garage. I can get my EX in for its frt aussie locker install