Turns over but wont start

[radd5]

I diconnected the inlet fuel line to fuel filter and cranked the engine. No gas flow. I did a system diagnostic to see if fuel pump was the problem (bridged terminals +B and FP at the check connector) and fuel pump did not work.

Then I tried to run a system diagnostice to see if a system diagnostics would tell me anything (after all I don't want to drop the tank unless I know its the fuel pump) but the check engine light does not work (therefore no diagnostic codes). Using the OEM repair manual I performed the trouble shoot tree for the check engine light and results indicate a "try replace ECU" or "ECU E1 ground problem". The E1 ground to body looks fine, assuming the E1 is grounded to the throttle body (it's hard to tell where all those wires lead to).

My question, can an ECU failure mimic a failed fuel pump? What are the systems of a failed ECU?

Some background: the cruiser's been sitting for four months because it died on me going home in December and I'm now getting around to fixing. In December I was driving in the rain and went to turn the lights on and bam...it totally died. It wouldn't crank, no lights, nothing. I had it towed home and it's been sitting sence. I initially thought it was the alternator, but it tested fine. The batter was dead (but that tested fine too). Charged the battery and it cranks strong and steady.

Sorry for the novel.

 

[cruiser88]

fuel pump ya need on

 

[cruiser88]

opps read back fuel pump nothing to do with it not charging

 

[cruiser88]

start checking all the stupit stuff fuses wires and such im sure its something dum

 

[mudpaws]

Remedy?

Hey, I saw you were having a little problem. Simple things like loose/heavily corroded battery terminals can cause any car with an ECU to "just shut off" while driving. Now- if you jumped out the fuel pump and it doesn't spin, it's shot. Replace that. I wouldn't touch the ECU as yet. First, replace or fully charge battery; I'm assuming, like you've said, that the alternator is good; Next, check for ignition ("spark"). Do this using an inline tester at a spark plug. On an old 60s/70s car, you can just ground a screwdriver between the disconnected plug wire end and the plug; However, I'd never recommend doing this to ANY vehicle with an ECU. Let me know how you make out up to that point. HTH

Ralph
TLCA# 3123
1986 FJ60

 

[getto]

I had similar problems with my 89-turns out it was a bad EFI relay. Just a thought.

 

[radd5]

Well my sage continues...

I've done a pretty thorough analysis of my electrical system. In testing the ECU, I'm getting off spec voltage readings from computer ground and the three EFI main relay's; and the computer ground and Battery. Readings taken at the ECU terminals. All four measure 2 volts...should measure 10-14 volts) while ingnition is on. The battery reading is 12 volts at the posts. EFI main relay checks out OK and the fusible link is brand new.

Since i'm getting some voltage, i'm thinking it's either a wiring problem or the ECU is shot. The wires seem to be in good shape, but who knows whats going on under all the electrical tape and grime.

I really don't know what else to do but buy another ECU and/or a new wiring harness. Suggestions....

Anyone have a good source for ECU and wiring harness?

Thanks for you help!

 

[radd5]

Fixed

Two words....fusible link.

 

[YODA 88 62]

now figure out why it blew the fusible link.

 

[mudpaws]

Perhaps a past jump-start not connecting NEG to engine ground, and instead to (-) batt terminal? That's one thing that could melt/weaken a FL. I've seen FLs last 20+ years, and others last only a couple before failing. They're there to do their job, protect the circuit from a current overload, saving high-dollar components like ECUs, relays, switches from certain demise.

BTW, which fusible was bad?

Nice job, way to check the simple stuff first!!! Cruiser88 and I were rootin for ya

Paws