When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
*I forgot
My TPS connector broke when unplugging it. It's mostly in place, but the wire retainer is... sketchy...
Could this cause the bogging? Seems like a TPS symptom in any other vehicle I've owned.
*I forgot
My TPS connector broke when unplugging it. It's mostly in place, but the wire retainer is... sketchy...
Could this cause the bogging? Seems like a TPS symptom in any other vehicle I've owned.
There is a cold start enrichment programmed into the ECU, it feeds a little extra fuel while it brings up the coolant temperature. So it runs rich when you goose the throttle cold it throws in more so it can go really rich and tends to have that lag.
PAIR system, pulsed secondary air injection system. AS valve and its other bits... It feeds fresh air into the exhaust to minimize emissions, it allows for a secondary burn in the tail pipe..
Dashpot, it slows down the throttle snapping shut on a manual transmission. Two purposes. First there is a chance for the engine to stall, second is a chance to cause a lean condition with the drive shaft spining the engine.
TPS, it would be more continuous if it was fallen off. For piece of mind wire tie it to another wire. (The tps plug on my turbo the whole shroud is broken off, just a friction fit its never fallen out)
There is a cold start enrichment programmed into the ECU, it feeds a little extra fuel while it brings up the coolant temperature. So it runs rich when you goose the throttle cold it throws in more so it can go really rich and tends to have that lag.
PAIR system, pulsed secondary air injection system. AS valve and its other bits... It feeds fresh air into the exhaust to minimize emissions, it allows for a secondary burn in the tail pipe..
Dashpot, it slows down the throttle snapping shut on a manual transmission. Two purposes. First there is a chance for the engine to stall, second is a chance to cause a lean condition with the drive shaft spinning the engine.
TPS, it would be more continuous if it was fallen off. For piece of mind wire tie it to another wire. (The tps plug on my turbo the whole shroud is broken off, just a friction fit its never fallen out)
Dashpot: Interesting. Perhaps I should adjust that set screw to make contact. But the rod exiting the diaphragm is already all the way down. Doesn't seem like it would help any.
TPS: I didn't think the TPS connector had fallen off. It's still on there, I was just thinking maybe it was making poor connection, and the temperature thing was coincidence. The connector is slightly loose. I suppose it's an easy enough theory to test next time I'm under the hood. Hold the connector, see if it changes it. I just didn't connect those dots until I was back inside for the night. Also, I noticed one of my mounting tabs for the TPS itself is cracked, but it seems to be still holding in place.
But this bit about running rich on startup. It didn't smell rich, but that's not always a fair test now is it? Although the (one piece of) data thus far seems to indicate a temperature related correlation. If it is essentially flooding itself now, is there an easy fix for that? Or... did I just screw myself with the questionable injectors?
Meh, just give it a bit of warm up time before you go drag racing.
Here is my tps.. Now im looking at it i think there is a little smear of that permatex inside the plug housing also.I did wind up changing that out for a slightly less worn one, but never went back and did the calibration I did on this one. Note calibration isn't just the FSM idle adjustment, that part I set within specs, calibration entails fiddling with the micro adjustments to keep IDL in spec and get the best range of throttle angle registered at the ECU.
I was not aware this was even an adjustable part. I'm going to have to take some time to absorb that all. At first glance your link is all... well, probably out of context. (*edit, just realized there's a bunch of pictures missing that would probably give that context). 'll dig further.
Looks like you know what I mean about the broken tab...
And as usual, thank you very much for the info.
There is a cold start enrichment programmed into the ECU, it feeds a little extra fuel while it brings up the coolant temperature. So it runs rich when you goose the throttle cold it throws in more so it can go really rich and tends to have that lag.
Another thought. Since I had the battery cables off, I'm assuming the ECU reset. Could this just have been it finding its legs again? (new injectors with different resistance values also)
Another thought. Since I had the battery cables off, I'm assuming the ECU reset. Could this just have been it finding its legs again? (new injectors with different resistance values also)
It is also open loop when cold, no oxygen sensor feed back.
Your injection flow rating (cc or lb per minute) will have an effect here.
Resistance will effect the "ramp time",
Looks like you hit the trifecta, and the warm up enrichment still plays a part too.
And while I'm postulating, does anybody know why I can find a throttle/ accelerator cable for any other year truck, but they all say they won't fit an 88?
So... hypothetical here. Gears in my head are just churning, and I cant get to it to try to duplicate yet.
If I am now running rich, and that's the issue cold... couldn't I just back the AFM off a click or so to fool it into line?
I guess I really need to bite the bullet and make an AFR gauge to slip in the tailpipe. Would have come in handy a number of times by now.
It's only rich while it comes up to operating temperature, like 140 or something then after 160-180 or so it goes into closed loop and starts reading the oxygen sensor.
If after driving it a few times at moderate throttle over 50mph it throws a trouble code for over rich trim level exceeded, that's when you should be concerned. It has a really small table (not many cells) compared to some modern stuff, like 8x8 or something ridiculous, so it will learn pretty fast.. There should be a diagnostics flow chart in the FSM, iirc, to replicate fuel trim issues.
Well, that's interesting. My temp gauge doesn't have numbers, just bottom, top, and red.
So I ran it for a few minutes tonight. Still bogged cold. So I took it for a test drive, because that normally gets it warmed up. Well... it's 60 degrees out. I made a lap that normally causes it to do the no-start.
Short story, it restarted repeatedly. But it was also still bogging.
Long story, it never got to full operating temp, where the bogging stopped last night. After 10+ minutes of idle time and 5-6 minute drive, the needle wasn't even horizontal. Not sure what that's about. I do have a failsafe thermostat, but... it's never been hot enough to stick open. I've revved the pants off of it though. But I seriously doubt I could have stuck it open by flow force.
in conclusion... results were inconclusive. But I did get a nice obnoxious exhaust video out of it with the Go Pro.
So, has anyone ever used one of these a banjo bolt with the NPT female threads on the back and installed a Schrader valve instead of a gauge? I would think this would be more convenient diagnostics, as you could just remove the gauge when not using, and it would be like the umpteen other fuel systems I've worked on that have a Schrader valve factory installed.
Sounds like more things to keep/lose and break.
I'd rather replace the gage with electrical sender and connect it to display that stays on the dash.
That's actually what I was looking for when the Schrader valve occurred to me, but at a fraction of the price. And I already own a pressure gauge that attaches to Schrader valves.
And, technically, both the transducer and the Schrader valve are the same number of threaded connections to come loose... If that's a concern, then so is the banjo bolt.
Yes, the valve going bad and having to keep the gage in the tool box (I like to dispose of things I don't need to minimize clutter).
Just have the banjo bolt adapter (LCE) and transducer screwed into it. Mechanically sealed so less probability of a fuel leak. Then just wire(s) to the display on dash. Because display is right in front of you at all times, will also always show effect of fuel-pressure up valve at temperature as you attempt to start.
02-22-2018, 06:46 PM
