My wife's bronco died!

[Jesus Freak]

So, all cupholder comments aside, yesterday my wife calls me from the feed store saying the bronco won't crank up. Spins, but no start. My daughter rescued her and I had to tow the bronco to the house when I got home late last night. This is an 86 5.0 EFI. I've been messing with it all morning and I'm at a loss. It's got spark, it's got fuel at the rail, I've swapped ECMs, I've swapped MAPs, I've unplugged the TPS, I've checked the ECC relay, I seemed to get a response from messing with the air temperature charge thingy but it was a fluke, I've wiggled this and that, I've remonstrated, I've demonstrated, I've prostrated myself at the mercy of whatever I could think of. Even messed with the ignition switch on the column just in case. My wife said she saw a tinge of smoke come from under the dash, I got the ignition switch to replicate that but I even tried a different switch just to see. Well? What do y'all think? The stock cup holders suck but they shouldn't affect the fuel delivery.

 

[Rdnck84_03]

So will it hit off a Huff of ether? My thought is that it isn't triggering the injectors for some reason. I am not very familiar with the injection system used on these, i do believe these engines are batch injection. Does it use a crank sensor on the harmonic balancer to tell the pcm when to fire the injectors?

James

 

[Jesus Freak]

I did try a "huff of ether", nothing. And they didn't have a crank position sensor on the drawing board back then. I'm not exactly sure what's telling what when to fire.

So will it hit off a Huff of ether? My thought is that it isn't triggering the injectors for some reason. I am not very familiar with the injection system used on these, i do believe these engines are batch injection. Does it use a crank sensor on the harmonic balancer to tell the pcm when to fire the injectors?

James

 

[Rdnck84_03]

If it didn't atleast try to hit with ether. To me that either means the spark isn't strong enough to fire under compression, or for some reason the ignition timing is way off.

I would bring #1 up to TDC and make sure the distributor is still where it is supposed to be. The first 2 things that pop into my head are the roll pin on distributor gear or the timing chain.

James

 

[Cant Write]

Time for a step up in reliability.........CARB-ER-RATOR

Just kidding!!

Can you use a timing light to see the injectors are firing like on a TBI? I’m in agreement with @Rdnck84_03

 

[Jesus Freak]

If it didn't atleast try to hit with ether. To me that either means the spark isn't strong enough to fire under compression, or for some reason the ignition timing is way off.

I would bring #1 up to TDC and make sure the distributor is still where it is supposed to be. The first 2 things that pop into my head are the roll pin on distributor gear or the timing chain.

James

I almost pulled the distributior earlier.

 

[Rdnck84_03]

@Jesus Freak I would roll #1 up on the compression stroke and check to see where the rotor is pointing first thing. No point in pulling things apart that don't need it.

James

 

[Jesus Freak]

@Jesus Freak I would roll #1 up on the compression stroke and check to see where the rotor is pointing first thing. No point in pulling things apart that don't need it.

James

Agreed! I did that and it really appeared to be retarded too much. So I pulled the distributior and it's legit, I even put another in and set it really close to where it should be and nothing, so dang! Maybe the timing chain is wonky! And hey, don't think I've been buying parts all day, I got a "parts bronco" and then a bunch of extra stuff for times like this. If you can change a bad sensor for a decent sensor, it should make it act at least different........ sometimes. So unless y'all come up with a different idea, I guess I'm pulling the front of this thing apart........DANG!!!!

 

[Rdnck84_03]

Have you tried swapping the coil? After that my next check would be a compression check, if the timing chain jumped very far the compression should be low.

James

 

[Jesus Freak]

I haven't swapped the coil, but it's shooting good spark. I'll see if I can come up with a compression tester tomorrow.

 

[XOLATEM]

86 5.0 EFI.

if it is original...this is sequential FI and it does not have a mass air flow sensor...it is the early style that uses a MAP sensor... Speed density...Mass air was 1987...

The first thing to do is take the dist cap off and see if it is turning....if yes...then turn the engine clockwise with a socket on the crank and then go backwards and see how far you have to turn before the rotor starts turning the other way...small distance...? OK....big distance..? slop in the chain...timing will be off...at least extremely retarded...

The crank sensor should be in the module in the distributor...IIRC...I could be wrong...it has been a long time.

I had a roll pin shear in the dist gear once...middle of winter...I had put an aftermarket electronic ignition in a stock dist.

The dist was stuck in one position and firing on only one cylinder and Boy was it firing....a continuous electrical surge on one plug...

If the timing chain is good and the base timing is close...I would swap out your spare dist and make sure it is lined up correctly and the plug wires are in the correct rotation...I am suspecting the module in the orig dist.

Did you check for spark on more than one cylinder..?

 

[Jesus Freak]

I haven't wiggled the crank and watched the distributor, but I did swap it out because it appeared retarded. I checked the spark at one plug and then the coil.......it's shooting lightning. It is a MAP, I swapped it to no avail. I'll do the crank wiggle and compression in the morning.
The original distributor was fine as far as condition, roll pin in place, tight bushing.

 

[XOLATEM]

Can you use a timing light to see the injectors are firing like on a TBI?

The tool companies sold 'noid' lights...set of eight...you connect them to the injector connector and watch to see if they light up in sequence

 

[Jesus Freak]

The tool companies sold 'noid' lights...set of eight...you connect them to the injector connector and watch to see if they light up in sequence

I think its more sinister than injectors. The bronco has been basically problem free since I got it and got it running.......... the piper is calling.......... and he wants to get paid!

 

[XOLATEM]

the piper is calling.......... and he wants to get paid!

I had a Lady customer once tell me that the 'Check Engine' light was really a "The Truck Wants Money' light...I had to hold my composure...she was from the former Czechoslavakia and I did not know if I would offend her...