Mysterious issue with 1990 MM 2.4L

[BillHilly]

I have a 1990 MM 2.4L 4G64. Recently, I had the water pump break and I had to haul ass home. I ran 12 miles for 75MPH while it was below 30 out. The truck never hit the red line on the temp, and it made it home and backed up and I turned it off. It wasn't pinging or any such things. Now, it will not start.

I've replaced the water pump. I made sure to check all the timing and reline everything up. I put it to TDC on compression stroke, and every single notch lined up, from the crankshaft to the camshaft, oil pump and balance shaft. I experimented with flipping the plug wires, but it is new wires, plugs, cap and rotor bug. I found the truck was a quart low on oil, but it burnt oil beforehand and I figure running it like an air cooled go-cart didn't help. The most I've gotten was a backfire.

Now, the engine isn't like the majority of the 4g64s I've seen online. I think it's the original style. It uses a spring style tensioner for the timing belt. I think it is the 8 valve SOHC, because that is the one I've seen is a non-interference motor, and I have heard no noises cranking the motor with a starter, by hand, or driving it home that would have remotely sounded like what I imagine a bent valve would sound like. I have a remanned ECM with less than 5K miles on it that I installed when I bought the truck, and played with the timing, to get it to start and run. The truck has a new fuel pump, filter, plugs, wires, distro cap, rotor bug, and starter.

When I changed the water pump I did have to pull a chunk of fin out that tried to go into the hole into the block. But I hear NOTHING rattling around. I can smell gas and see it on the plugs, at least plug 1 and 4, and both sparked. The spark seemed to go between a blue fire, and a yellow fire.

Please, any advice would be greatly appreciated. Do I have to get a new ECM because my remanned decided to do the notorious thing of screwing up on the injectors?

[FMS88]

Have you run a compression test?

[BillHilly]

No I haven't. The truck doesn't sound different cranking over really

[FMS88]

If you didn't loose coolant or the pump didn't seize up, you're probably fine. It's just that a compression test is a good
diagnostic test after an event that could have harmed the basic engine components.
If playing with the timing got it started before, it might help to repeat those now. However, I'm a carburetor guy so those with FI experience are better suited to offer counsel. Hopefully they'll join in.

[geezer101]

So the rotor is pointing @ post 1 in the distributor cap TDC? And have you put the ECU into diagnostic/tune mode by grounding the connection in the engine bay? Sounds like it's only a timing thing if you are getting injector pulses and there's spark... check and recheck

[BillHilly]

So the rotor is pointing @ post 1 in the distributor cap TDC? And have you put the ECU into diagnostic/tune mode by grounding the connection in the engine bay? Sounds like it's only a timing thing if you are getting injector pulses and there's spark... check and recheck

Ah I did not put it into diagnostic mode. And my father told me it was pointing at cylinder one when at TDC. It would only crank over, never try to catch. So, I hook like a little alligator clip to that little connection and just clip it to a piece of metal, time it and get it running, then shut the truck off and unclip it to set the tune?

[geezer101]

Yep. Just ground it while tuning and it will reset the base timing. You have to get it to fire first though or you're not tuning anything. You can also get it to dynamic tune as well by holding the rpm's @ approx 2000 and gently rotate the distributor until you get the rpm's to spike by themselves. Once you hit the sweet spot, lock the retaining nut in place. If you want to perform the dynamic tune, first regap the plugs to 0.85-0.9mm. It will have a more aggressive acceleration curve and shift better.

[BillHilly]

Thank you dearly. i've been wondering why it's doing what it did. I never set it to diagnostic when I redid the distro timing last. So I'm gonna set it to diagnostic, make sure it's at TDC and all in time, and set the distributor to plug 1. If I get it to run at that then I tune it in and shut the truck off, and unclip that? It sparks and all and is in time but not wanting to run, so I think it may be slightly off. The belt was rather loose when I got it all apart so I fear the belt stretched.

I just got fired from my job on christmas though, so I finally got time to actually spend a day redoing it all. So if I get it tomorrow I'll update! Thank y'all for the advice!

[finalfighter]

take a little bit of starter fluid and spray it down the throttle body. if it fires up than the fuel pump went bad. another thing to try is firing it up with the MAF disconnected. also try disconnecting the two connectors on the passenger side on the firewall in the engine bay and spraying them out and plugging them back in. those two go to the distributor and injectors. i have to do this regularly for some reason on my 1992 when it gets really cold out and i try and fire it up in the morning.

[BillHilly]

Okay I shall do so! I replaced the fuel pump with a brand new quantum pump about a day after I got the truck started. It ran for a day then the fuel pump died. But I shall clean that connector and try the MAF because duh, I forgot the truck has a MAF sensor and I know that if you take the intake hose assembly off while it's running it dies and revs down instantly. No hesitation it kills it instantly.

[BillHilly]

So I got it all the marks lined up again. Here are the photos. I'm pretty certain the distro was pointing at my number four plug. I followed the line after taking it off. So would I reassemble it all and just flip my plug wires? How do I reset the distro? I know to take it out and line the dimple up.

[BillHilly]

Also I took all four plugs out. I can smell fuel on them but they are all dry after multiple tries cranking the truck.

[BillHilly]

[BillHilly]

I lined it all up and tried to reset the distro again. But if I line the dimple up and try to slide it all in it won't line up with the stud, and instead will twist itself like a quarter turn and lock itself into place. But it won't go in smoothly at all. It has to rotate.

[finalfighter]

got to post #11. i posted pictures of how everything will look when its all times

http://www.mightyram50.net/vbulletin...98-Timing-Woes

[finalfighter]

here is also a good thread. i posted pick on post #15

http://www.mightyram50.net/vbulletin...timing-I-Think

[geezer101]

I lined it all up and tried to reset the distro again. But if I line the dimple up and try to slide it all in it won't line up with the stud, and instead will twist itself like a quarter turn and lock itself into place. But it won't go in smoothly at all. It has to rotate.

That's how it works. When you insert the distributor gear, it will cause the shaft to rotate into position. The rotor should be pointing to the leading edge of #1 post in the distributor cap if you've installed it correctly.

[BillHilly]

Okay so I set all four plugs onto the block at night and had my gf fire it over. It seems all four plugs are sparking just fine. Here is the video of the plugs.

[BillHilly]

So, how would I go about testing my injectors? To make sure it's getting fuel to each cylinder? Would I take the injectors out and test them with a battery? But then how would I test that the ECM is actually firing them?