ChrisInVT

Well I hate the fact that my first post here is a "help me" thread, but so be it.

I have a 1989 1-ton box truck with the 3VZ engine. The truck was running great all along, and one day it just died. After a long trip I stopped to eat, when I was done I went outside and started the truck, put it in reverse, and it died. The symptom? No fuel getting to the engine. It would start on starting fluid, but the pump wasn't kicking on. Ended up getting the truck towed back to my house, only cost me $320.

Anyway, when I got the truck back to my place I put it up on the lift and was checking around to see what the problem was. Low and behold, the positive wire on the fuel pump was corroded and broke in half. I fixed the wire and the fuel pump worked when I moved the swing arm on the VAFM. I thought I was going to start the truck and drive it out of the shop, but that wasn't the case. Now I had no spark!

I don't have a repair manual for the truck so I found this thread and used it to troubleshoot: https://www.yotatech.com/forums/f2/n...89-95-a-10543/

The resistance for pickups in the distributor were a bit off, but I continued anyway. The writeup said that if they were bad, the "tap test" wouldn't work. When doing the tap test, I got spark from the coil. When I got to this part I had a problem.
When I did the tap test with the second light attached, the second light flashed. So there we have it, bad coil right?

I continued through the tests so I was sure that was the problem. I have continuity on the Black/White wire between the igniter connector and the negative side of the Coil and the igniter itself is grounded properly, no rust or corrosion. I also made sure the Black didn't show full continuity to ground.

Now the last part stated:
I didn't really understand the whole "primary side" and "secondary side" so I didn't get to test that part. Anyway, I checked the distributor and that seems to be OK, no broken stuff, rotor spins when cranking, timing is OK, no broken wires.


So I replaced the coil/igniter assembly with a used one, and I still don't have spark. All fuses check out OK and I checked the wiring going to it and those seemed OK. Can't exactly check every wire since there's about 15 thousand on the truck. Not sure what I should check next.


It's just very strange how it has a no spark condition after the fuel pump wire broke.

ChrisInVT

40 views and no posts? C'mon guys.

I'll add a pic for justice.

sb5walker

primary between pos and neg terminals (make sure all wires disconnected)
secondary between pos terminal and high volt cable (that goes to distrib)

These posts may have something helpful:

http://www.toyotanation.com/forum/sh...06#post3022306
https://www.yotatech.com/forums/f116.../#post51130411

ChrisInVT

Alright, I need to check the camshaft and crankshaft position signals then...

I'm now the proud new owner of a Toyota camper that I'm going to be stripping. There's actually nothing wrong with it other than the bathroom was torn apart for an upgrade, but I'm going to strip it and use it for parts for the box truck. Low mileage too, only 75,000-ish. Hell of an upgrade for my truck which has around 250k on it.

ChrisInVT

I still haven't gotten the truck running. It's been sitting in my yard for some time after I replaced that coil and it still didn't run. I actually had my girlfriend take the coil from my truck and put it in the camper (numbers matched) and it fired right up, so I know the coil is good. I'm still leaning towards the crankshaft/camshaft position sensors as being the problem (hopefully).

The linked article states this about testing them:

That makes no sense, since none of the wires are labeled. There's four wires coming out of the distributor. Red, Green, Beige & a slightly darker Beige. There's no G1, G2, G- & NE.

sb5walker

If you follow the links to the factory service manual in one of those posts you'll see that the G1, Ne etc are the labels in the manual for the leads, the actual wires aren't labeled - they are color-coded. In this case, the green is the negative lead (common): G- Since all three signal coils have the same resistance specs on the 89 - 140-180 ohms cold - just check for resistance between the green and each of the others.

If the wires on the harness side of the connector are different colors (that might be the case if the distributor is aftermarket), use the harness colors.

Here's the fsm section for the 93 truck, which has slightly different specs and a different connector. But basically the same design and the same four leads:
http://personal.utulsa.edu/~nathan-b...12onvehicl.pdf

Have you checked for codes? There probably are some stored in the ecu and they might tell you where to look. Instructions here:
http://personal.utulsa.edu/~nathan-b...85diagnosi.pdf

ChrisInVT

I figured such, but I didn't see the connector in any of those PDFs I downloaded, I must have skimmed right past it! I'm downloading the complete FSM now from ncttora.com, hopefully that'll help me out some.

I didn't check for any ECU codes because when the truck died, and I couldn't get it started after fixing the fuel pump, I just pushed it out of the shop and let it sit until now (the snow has FINALLY melted up here). I don't drive the truck in the snow for obvious reasons, so it was on the back burner for a while. Just started messing with it again today because I got bored. Since it was sitting I disconnected the battery, so I figured there aren't going to be any codes stored. Think the ECU is smart enough to know what's causing the no-start issue since it's been reset?

Oh, as a side note - the green isn't the common on my distributor. The crank sensor has a beige and a colored wire, one cam sensor has two beige wires and the other has a beige and a colored. I haven't found out which beige is the common yet, but it should be easy enough to do. As soon as I disconnected the connector to start testing with my multimeter, we got hit with a torrential downpour so I went inside.





EDIT: Just went outside in my PJs and checked since it finally stopped raining. Looks like the light beige is the common ground. Measurements I got off the sensors are 168Ω for camshaft one, 169Ω for camshaft 2 and 170Ω for the crankshaft. So much for thinking my problem lied in those sensors.

What could possibly cause a no spark issue with a broken power lead to the fuel pump? I mean, yeah we tried starting it over and over; but it fired up on starting fluid right up until he point where we loaded it onto the flatbed. Then I got it home, fixed the broken wire - and no spark! I'm hoping the ECU isn't fried - but it seems like that might be the problem. I was thinking the VAF could be bad, but if I move the vein with my hand I can hear the fuel pump kick on. I should probably test that too anyway. Too bad my camper and this truck are 20 miles apart and I need to explain to my girlfriend how to swap parts so she could test them for me...

sb5walker

http://personal.utulsa.edu/~nathan-b...fsm/index.html It's for a 93: the distrib, coil specs, throttle body and timing belt idler arrangement are slightly different, but very close, and almost everything else is either exactly the same or only slight changes. I've never seen an online manual for 89-91 trucks.

Reason I mentioned the harness side of the connector: one of those wires should be green, and is the common, and all you have to do is see which wire it connects to when plugged to the distributor.

You have to check not only coil resistance but signal rotor clearance also to be sure, but on the 3vze I've never heard of those being out of spec. Doesn't mean it couldn't happen.

If you have seen the check engine light come on when you've tried to start it, then the ecu has been powered and probably has stored some codes, which could help you.

BTW if you haven't seen the CEL come on, verify the ecu has power by checking that the +B terminal in the gray plastic diagnostic check connector on the side of the fuse/relay block on passenger inner fender is hot when ignition is on.

The fuel pump power circuit and ignition circuits are, I think, almost completely separate. So I doubt there is a causative connection, unless there is a ground fault somewhere. It would probably not be a bad idea to check the grounds. One thing that is not too difficult is to verify both engine & chassis have good connection to neg battery post. Also open up the check connector and make sure you have a good connection between E1 and the neg batt post - that's the ground the ignition system uses.

There may be an issue in one of the leads between signal coils & ecu or between ecu and igniter. But if so you should have a code.

ChrisInVT

I edited my previous post, the timestamps show you were typing while I was editing Not sure if the info I added will help or not. The manual I downloaded is for the '88, I haven't seen ANYTHING on '89 model trucks - not even in the autoparts stores. It's like they never existed. You were right about the harness side, it connects to the light beige wire. That's my own fault for reading and then going out to the truck and tinkering. In the 20 feet I had to walk outside, my brain decided it would be fun to mess up the instructions

I have the VAF in front of me right now (went outside and pulled it off the truck, even got to loose the metal retainer clip in the dark when it went rocketing off. I'll never see that again). One of the Ohm ranges are a bit off. VS-E2 is supposed to be 200Ω-600Ω and that gave me a reading of 610Ω which is 10Ω too high for the high-range. VC-E2 is supposed to be 200Ω-400Ω and that checked in at 281Ω, THA-E2 checked in OK at 2.8KΩ @ 60*, and FC-E1 checked out OK at ∞. I'm going to see if I can talk the gf into pulling the VAF off my camper (hopefully without loosing the metal clip on that one too).

I've verified that the ECU has power by checking the B+ terminal previously, and also again today when re-tracing my my previous steps to see if I missed anything. I've checked the grounds between engine/body/battery and they all seemed OK (read same voltage between everything & only slight variation in Ohms). The CEL is NOT illuminating at any point in time, but IIRC I had a problem with several lights intermittently working on the instrument cluster that I didn't have the time/patience to fix when I replaced the heater core. I don't remember if that was one of them or not. Without pulling the dash apart again (God that was a nightmare) how can I test the CEL to see if it's a problematic light or a fried ECU?

I haven't gone through the 1,468 page FSM yet to see how to pull codes.

ChrisInVT

Well, I got the truck running again - and I feel like an idiot.

I replaced the VAF with the one from my camper, and still the truck wouldn't start. It would crank and crank and crank but never fire. Same symptom, no spark. Last thing it could be was the ECU. Well, I got in the truck and I was going to pull the plugs and remove the ECU when I noticed the first plug I pulled on came out a bit too easy. I plugged it back in and heard the snap from the connector. I tugged on it again and it didn't come out so easily. I turned the ignition because I was curious about this connection - and sure enough it fired right up.

It seems that my girlfriend was nice enough to kick the computer and knock one of the wires out - which caused the truck to die. I must have broke the already corroding wire on the fuel pump when I crawled underneath the truck and tugged on the wiring harness to see if the connection was loose.

So now the truck runs fine, who would have thought. I tested some of the wires on the ECU but never tugged on them to see if they were fully seated. Why would I, it's not like those things EVER come unplugged!! Oh well, it runs now so I'm happy. Only problem is now I have a fuel leak - seems like I need to replace the fuel pump holder thing because the high pressure metal line has a pinhole in it.

It never ends.