need local help...

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

I feel like we're throwing parts at it to fix a problem we haven't identified.

Help me build a list of what you've done:

1. replaced injectors (OEM new or reman or ?)
2. replaced injector connectors (soldered in I hope?)
3. replaced EGR valve and inspected harness around EGR (all checked out good)
4. replaced intake tube
5. pseudo-cleaned the throttle body
6. installed used TPS
7. cleaned idle control valve


What ever happened to the vacuum tube/cap you said you had a hole in?


Any codes now that it's back together and running?


I'll give you $100 for the truck :steer:
 
I feel for you, early fuel injection is wizardry on a good day. Playing catch up on years of neglect does not improve the situation. I am of little help, I'd rather do a swap than fix the stock motor. :)

Hope it is something simple you missed and all goes well. Keep the faith and listen to the guys that have been down this road.
 
I can do a little better than $100. :D

What would you like for it?
 
Johnny is on the right track about stepping back and compiling a list for everyone again (although not a bad thing those parts got replaced if the truck really was neglected that much)
 
All the things you listed Johnny plus:
Injectors are reman units w/OEM parts
Denso injector plugs (soldered and heat shrink)
NGK plug wires
NGK plugs
Cap and rotor
EGR is gone now/blocked off
Main harness is insulated after being checked
Leaking vacuum hose removed and capped
TPS adjusted but a new one is on order
New vacuum hoses under upper intake
New fuel pump and filter
IAC cleaned a few times

No CEL's. It does seem to idle better with TPS unplugged...also I can't seem to get it close to factory spec timing without it running like crap (in service mode)
 
Last edited:
Running better after tps is disconnected is very concerning to me. It should run much worse if not at idle, at all other engine speeds. Do you have an oem replacement? I would suggest replacement just based on the fact that it seems to run better after tps is unplugged.

Which vacuum line did you plug specifically? Unless the truck is desmogged or otherwise modified, all vacuum lines should be connected as per the factory diagrams. I understand that the egr valve was removed, but was the associated pipe to the exhaust around the back of the head? Did this same problem exist before the vacuum lines were changed?

About the timing. Can you post a pic of how the Dizzy is currently aligned? When you set the timing did you use the fsm procedure or go just by the timing light? Last time I installed a 1fz Dizzy I went by the fsm procedure (without a timing light) and got a motor that ran damn well, so the timing problem is a concern for me as well, especially because an earlier post seemed to indicate that the majority of the off-idle issues started after timing was adjusted. Just because timing set at idle makes the engine sound good does not mean thats the timing the engine is supposed to be set at. I've been fooled by that before.

My suggestion is to reset timing based on the fsm distributor installation procedure. Once done, regardless of how it idles, (assuming it idles) take it for a drive and tell us how it runs.
 
Not trying to be critical of your work, just trying to apply critical thinking to your problem so that we can get the truck running properly :cheers:
 
No criticism taken, I appreciate the help. I drove it around with the tps unplugged and it won't get over about 30 mph very easily. It idles a little better just sitting, but I'm getting the same intermittent idle after driving it. As far as the timing goes, I set it off of lcool.org. It seemed to be FSM type instructions, but I can't confirm that. The truck is desmogged as far as EGR and PAIR valves being removed, so there is nothing left to hook those associated vacuum lines to. It's always had the idle issue, even before that stuff was removed. The off idle hesitation is more recent though. It didn't start til after we adjusted the timing initially. I would have never touched it, but it had a bad dead spot up until half throttle or so. I thought advancing the timing might help that some. I didn't order an OEM replacement TPS, just an aftermarket unit from rock auto.
 
image.webp
This is sitting at about 6-7 degrees...before I messed with it the distributor was damn near at the top of the adjustment slot. When I put it back to that position though I still get the hesitation, though it may be in a higher rpm range. It still runs bad regardless.
 
Last edited:
I trying to download an FSM but not having much luck with the links I'm finding.
 
Yeah I tried that one. I click on the link and just get a blank screen, doesn't seem to be doing anything.
 
Just tried link on upstate , the thread is FSMs works fine .
 
I have the FSM and can email it to you or share it via dropbox. Send me your email.

There's an entire section on diagnostics. This specific section is for setting timing at idle. Please run through this procedure and report your findings. IMHO, timing needs to be set per FSM before we do anything else:

upload_2016-9-2_9-44-29.webp
 
This doesn't really add much to the thread, but I've always loved that a jumper wire gets the Special Service Tool designation.
Probably $40 bucks to buy this thing:
upload_2016-9-2_13-20-0.webp
 
After a test drive at 3 degrees timing per FSM instructions, hesitation is still there. It feels as if something is holding it back or choking it. It sometimes won't react to throttle input. It just stays a steady rpm no matter how far the throttle is depressed. Maybe TPS?
 
Are you going up a hill or something when this occurs?

Could very well be TPS. If you downloaded the FSM I sent you, follow the FSM to install your new TPS when it arrives.

Your first PM said that the hesitation was gone for a bit, then you took that statement back. Under what conditions does this hesitation occur specifically?
 
Nope, just flat ground. It happens under normal driving, nothing unusual. It comes and goes which makes it harder to understand. A few times from a stop it seemed the hesitation was gone. The very next stop and go, it might be back.
 
Gotcha, so it's intermittent. Stan is right in that because this EFI system is pre OBD2 we don't have the diagnostic or telemetry advantages of OBD2, so it's more difficult to figure out which sensor is malfunctioning.

I find it really hard to believe that there are no codes, especially because you completely removed the EGR. At very least there should be an EGR code.

Can you drive it for maybe 50 miles and let us know if the CEL comes on or if the driveability changes?
 
You must log in or register to reply here.

Share this page

Back
Top Bottom