Hello all,
I will try to keep this as short as possible, but there is a bunch to the story. Buddy has had his '89 since new but has sat for the last 20 years (last reg in '06)
He wanted to get it going so I took it on and started working on it. In short, the fuel tank, pump, hanger and sending unit all had to be replaced (found the hard way you cant get a sending unit with a dummy light for a 19 gal tank anymore)


Old fuel pump

After this, did plugs, wires cap n rotor to get it fired up and make a determination to carry on. It fired up, I rev'd it a couple times and shut it down. Sounded ok and decided to do the rest of the maintenance. Cooling system was pretty bad and evidence of head gasket seepage was found. Decided to do head gaskets, water pump timing belt, etc. Pulled the heads and they were so pitted, it wasn't advantageous to weld the pits and machine, so I had the machine shop source some heads.

Old head

Slapped the rebuilt heads on and reassembled. Starting it up, it definitely runs sluggish and is incredibly hard to accelerate (i cant get it out of 2nd gear because it wont build momentum). Addmitedly, I have no idea what it was really like before I tore it down. Aside from the new fuel pump, heads, timing belt, water pump, ignition components. etc, I did replace the distributor with an Amazon cheapy because the wiring had a bit of damage on the old one. I have: re-checked my timing to make sure the belt didn't skip a tooth, set base timing to 10° BTDC (it seems to buck at 10° *sometimes*) checked for compression, all are at 125psi, checked the VAFM and TPS. Used a cheapy tester to check the injectors and sprayed carb cleaner through them. I pulled the plugs and for being brand new, has an excessive amount of carbon (gotta be running rich). I replaced the vacuum hoses and smoke tested through the brake booster port on the manifold. There's nothing really screaming at me that anything is wrong. The only things I haven't checked are fuel pressure or if that cat is plugged. This behavior occurs in open loop and closed loop (normal operating temp) I have taped off the FITV port in the throttle body as a test and saw a bit of improvement in revving it up. The coolant ports were plugged on the TB and I have cleared them out as well. Apologies for being all over the place, it just feels like I've tried almost everything and nothing has worked out for me. Also, you can see in the before picture below, the EGR vacuum was routed in such that it bypassed the switching valve. I have replaced the 3 valves on the passenger side fender well as before it was brought to me, it was pressure washed and some of the valves got damaged. So the vacuum is routed as per the diagram.

Any and all advice is truly appreciated. Thank you so much. Please help me get this thing back to its owner lol.


Before

After

 

Oh jeez, that formatting is disgusting. I will re-edit it soon


*OP has been reformatted*

 

Tested fuel pressure: ~44psi @ zero vacuum and ~36 psi with 20 inHG pulled on the fuel regulator. So that checks out.
I did notice fuel pressure was dropping to almost zero within a minute. I think the check valve in the pump is good because it is a new Carter pump. Makes me start to think of leaking injectors. Unfortunately, this behavior stopped after I pinched off the fuel return hose and bumped the psi to 80 lol. Hopefully the pressure dropping condition returns and I can send a borescope and see if any injectors are leaking.

Next test is exhaust back pressure for a plugged cat. Does anyone have any known numbers to cause severe driveability issues with the 3vze?

Thanks!

 

Any codes? I would put the Oem dist. back in if it’s usable at all. Mine runs better at 12 degrees

 

Thanks for the response! Sadly no codes that were not self inflicted (vafm and tps codes when I disconnected them to test) and no codes since resetting. I'll run it a bit and see if anything wants to pop up I'm

Unfortunately, I cant use the old distributor, but it may be beneficial to scoop one up from a junkyard. The pickup coils are ohming out as they should (there are two differing documents out there: one that says all coils should be in the ?355?ohm range while the other has two at 355 and one lower) and i have the latter.

I'm going to do the exhaust back pressure check 5oday and see id i can get any info there. I'm still ruling out the o2 because the issue happens when cold. I'm going to do a resistance check at the ect sensor to rule out that it's not saying it's like -32° all the time or something. I know other makers will just dump fuel when that sensor says it's below freezing.

 

I had a pickup coil go bad in my dist.and I bought a salvage dist. off eBay. I was sure I would be better off with a salvage oem then I would with the aftermarket. If you buy from a seller with good feedback and they will guarantee that there stuff is good you should be good. Good luck with it, these old pickups are sure worth fixing.

 

So I did some testing on the ect sensor. Its about 90° in my garage. I tested at the ecu connector:

ECU connector Plugged in: 13kohms
ECU comnector unplugged: 150kohms

Considering sensor grounds come from the ecu, I am opting for the plugged in value. If I go off of the (what i assume is the correct) wiring diagram info it's-4°F....

This is also assuming there is scaling happening before it makes it to the ecu. Im trying to get to the sensor and testing it directly.

I know the ect sensor is a pretty vital component to the 3vze fuel management so maybe this is the smoking gun but I'm not keeping my hopes up.

As for the distributor, I rechecked the resistance measurements at the ecu plug and I believe everything checks out.

But definitely, these trucks are awesome, and it is even more so important to get it going for my buddy, it has so much more sentimental than monetary value!

 

OK! So I am dumb. I checked the ECT at the wrong ECU ground. Checking correctly, I get corresponding ohms to temp.

I decided to pull the plenum an check the spay patterns of the injectors. I thought maybe I had leaking injectors. That is not the case.

I started thinking more about the distributor I bought off Amazon and I think the coils are incorrectly wired. All measurements are good but if the 22re dist layout for G1 and G2 coils is correct, then G1 signal is going to G2 at the ECU and vice versa. Does anyone have a distrubtor you can check?

If this can be trusted:
" White..NE signal
Red..G1 signal
Black..G2 signal
Green..G- signal"


and the 22re dist layout can be trusted (I have 3VZE)


Then I believe they are wired incorrectly. This would make the cam to crank correlation off by 180°. It would still run, but run like a dog.....



What do you all think?