Fuel issues

[1986RangerXL]

Fuel injectors were not the remedy, sadly

 

[1986RangerXL]

Okay, now for a more comprehensive update.

The erratic idle has still not changed, when cold it idles normal, completely falls off a cliff for 2 seconds, then surges back to life. When warm it idles better.
Drove it yesterday after fuel injectors were installed, and it was borderline undrivable. Under load it misfires bad, when warm it misses occasionally.

It's worth noting that during the summer, I had none of these issues with the motor. It idled fine and you could rev it up and it was happy.

I know the TPS is bad, it will be getting replaced soon.

Here's what's done already: (Refresher)
New injectors, fuel lines, fuel pumps
Checked FPR for leak, fuel pressure reads normal
New plugs, wires, distributor
Alternator, battery, battery wires
IAC cleaned
Checked for vacuum leaks
Valve cover gasket, upper intake gasket
Radiator, ECT sensors

TPS is first on my list, considering a new coil and checking the plugs since the last set were fouled due to injectors and I think this set might be too.

I noticed white sludge on the oil cap yesterday, but no condensation on dipstick. Starting to become worried that the motor is junk.

Thanks for reading

 

[Paulos]

Sounds like your IAC. It's responsible for your idle when cold. "Cleaning" them doesn't always work. It's kind of a last ditch effort before you buy a new one.

Have you checked your vacuum lines for leaks or mis-routed lines?

Check the ignition coil for primary and secondary coil resistance. Check your plug wires for cuts, melted spots, poor connections, etc.

You mentioned you got a new distributor. Did you get a new ignition module also? Is it black or gray? Have you tried swapping the old and new modules to see if there is any difference in the way your engine runs with each?

Have you pulled codes off the ECM?

After watching the video I can't help but feel it's something in the ignition, or even the ECM. Definitely check the coil, swap the ignition modules, check the plug wires and distributor cap. I think I still have a working ECM from my deceased '86 2WD 5-speed Ranger (that I'll probably never use) if you want it. It's a E6TF-12A650-C2D ECM.

 

[1986RangerXL]

@Paulos
I checked the IAC to make sure it spun, but I think I should buy the ohmmeter to properly test it.

Checked for vacuum leaks, but tomorrow I will get out the owner's manual (or Chiltons manual) and run through all the vacuum lines.

Wires are new, but the last set of spark plugs were fouled, so I am going to check those. The distributor is black and was one-piece. I will look around to try and find the ignition module tomorrow. Will look into testing coil.

As for the ECM, when I swapped the body I kept the 2.3 cab harness in and only changed the engine harness. Does that cause problems? Thought the cab harness was plug and play with any ECM. Also I accidentally swapped battery terminals (it was dark, put the battery in backwards I'm am idiot I know), maybe that fried the ECM? Will check that too

A year ago I couldnt even change my own oil, so obviously a bit in over my head. I appreciate your help

 

[wildbill23c]

I'm not sure exactly how the ECM is protected or not protected, so it is possible that the battery connection backwards could have damaged it.

I also think a 2.3 wiring harness would certainly be much different than a 2.9 harness. The ECM is of course in the cab, and would require different signals from different parts of the engine and the 2.3 harness may not have those wires, or not where they are supposed to be connected, so that may be quite possible that the harness needs replaced.

Did this truck ever run correctly after the body swap?

 

[1986RangerXL]

I'm not sure exactly how the ECM is protected or not protected, so it is possible that the battery connection backwards could have damaged it.

I also think a 2.3 wiring harness would certainly be much different than a 2.9 harness. The ECM is of course in the cab, and would require different signals from different parts of the engine and the 2.3 harness may not have those wires, or not where they are supposed to be connected, so that may be quite possible that the harness needs replaced.

Did this truck ever run correctly after the body swap?

Nope, once the body was on we had an alternator fail and the starter relay. Got those sorted out now dealing with all this.

 

[wildbill23c]

Before throwing more parts I'd really install the right wiring harness. I know the ECM's between the 2 are different so pins may not line up on the new ECM so it may not be getting the proper information it needs.

I have an 87 Ranger 2.9L V6 right now that was bucking, lacking power, etc. I was slowly going through and replacing sensors, and everything I could think of and right after getting the truck I had replaced the fuel pressure regulator. After doing everything I can think of, I never thought about testing fuel pressure again after having a new fuel pump, fuel lines, fuel filter installed too. The new regulator at idle was only giving me 28psi, which is low revving the engine slightly dropped the fuel pressure to 10-15psi. I disconnected the vacuum line off the regulator, checked pressure again, at idle I was at 43psi yesterday afternoon, and applying throttle it would remain relatively the same.

I'm betting you got a fuel delivery issue possibly the regulator isn't any good. It don't require much fuel pressure to idle, but it won't idle properly. Also on the driver's side frame rail just about right under the driver's door there should be a fuel reservoir/filter, did you change that filter too? I believe there are 2 filters, the one that's in that reservoir, and one further up the frame towards the engine. That reservoir has a tendency to leak when the o-ring gets dried out, my reservoir assembly was cracked too and pouring fuel all over the place.

Just a few thoughts I've come up with after dealing with drive-ability issues with my Ranger. I thought my new fuel pressure regulator was good, turns out its not. Should be I think 30-35psi at idle, then jump to about 40-45psi with that vacuum line disconnected off the back of the regulator....plug the line or the port on the vacuum T, otherwise you'll have the engine running weird due to the vacuum leak LOL.

Also, double check all your vacuum lines to be sure you don't have any leaks, a leak can cause some weird problems.

 

[1986RangerXL]

Yup, I got 30-35 at idle and 40-45psi. Actually I realize now that the cab harness has nothing to do with it, the engine harness runs through the firewall and that's where the connector plugs into the ECM. The cab harness is separate. I am VERY suspect at this point that the ECM is failing, nothing else makes sense. I know things do go bad, but the IAC, Coil, Fuel system, ignition system all worked before the body swap. And I definitely mixed up the battery cables after the body swap.

 

[PetroleumJunkie412]

Get me the three digit code off your ecm. Probably have one. It's not the ecm that would fail - that can happen in rare instances, but more likely the electrolytic capacitors on the mainboard. If I have a good one of yours, I'll trade you your bad for my good if you cover shipping for both.

In the meantime,

Standard Motor Products Idle Air Control Valve https://www.amazon.com/dp/B000C7XPGW/ref=cm_sw_r_cp_apa_i_MaIqEbX89PJSY

Do not buy the slightly cheaper AC20T. 'T' means it's substandard motor products budget line.

Free 30 day returns, which means try it and keep it if it fixes the issue, return if it does not.

My 88 has killed three IACs, and I killed two with the megasquirt when I was figuring out how to get the engine to idle. Turns out idle is the hardest thing for efi to do.


Either way, $1 says iac. Engine uses more air on cold start than warm idle. If your solenoid has a dead spot in the area it doesn't use as often - ie - high idle area on the actuator rod, it's going to idle like ass when the iac can't fully open. So, it's starving for air, what the iac controls, but your injectors are pouring fuel down its gullet like a frat boy on St. Paddy's day.

Cheap test is to backprobe your tps at ignition on, not running, write down your signal voltage, should be 0.85-1.01 IIRC, and use the tps adjustment screw (a lot of people think it's a idle adjustment screw and eff up their ie by treating it as such), use it to prop your tb open a bit, and start it cold. If it's better, reset tb screw and toss an iac from Amazon on.

 

[PetroleumJunkie412]

Well. At least I sound like I know what I'm talking about.

@RonD any advice, Canadian God?

 

[PetroleumJunkie412]

So. Sh*t. I forgot you're 86. You have egr and knock. Fawk. Two systems I'm just now learning. I don't think they're in play here unless your intakes are sh*tted up. May be worth pulling your upper off and shooting some photos and cleaning. If you can dig up some of the pat Kuntz posts, he was constantly cleaning the sh*t out of his.

2.9s hate dirt.

They ****ing hate it. Some choices here on ways to clean.

 

[1986RangerXL]

I don't think they're in play here unless your intakes are sh*tted up.

My upper intake definitely was covered in a layer of carbon

So how do you check an ECM?

 

[1986RangerXL]

I opened up the ECM, no burnt smell or signs of burnt components. Checked the ECM plug, all fine. Made sure it was grounded properly.

It was warmer here today, so once it got warm I took it out for a drive. I drove it for around 20 mins and it was perfect! Foot to the floor (TPS unplugged) 1-4 gear no bucking no stalling. But then I killed it once at a stop sign. After that it started bucking and stalling again.

I'm with you guys on getting an IAC and a TPS to correct the idle problem. After that I will decide on replacing the ECM

 

[PetroleumJunkie412]

So, without a rotunda tool, EEC-IV ECMs are difficult to test. Yes, you can sit with a volt meter and test each I/O connection. However, the safest way is to look around under the capacitors for a leak. When an electrolytic capacitor dies, it usually poops itself all over the board under it.

Sometimes they only poo a bit, other times there's no poo. If you have a capacirence meter, you can check them individually. However, much easier to get on Mouser or Digi-Key and order the same as whats in there. Usually, this is all a "refurbished" ECM is - A junkyard pull thats been repainted, had a new sticker slapped on the case, and new capacitors (sometimes).

Sometimes the only thing new is the box.

 

[1986RangerXL]

So, without a rotunda tool, EEC-IV ECMs are difficult to test. Yes, you can sit with a volt meter and test each I/O connection. However, the safest way is to look around under the capacitors for a leak. When an electrolytic capacitor dies, it usually poops itself all over the board under it.

Sometimes they only poo a bit, other times there's no poo. If you have a capacirence meter, you can check them individually. However, much easier to get on Mouser or Digi-Key and order the same as whats in there. Usually, this is all a "refurbished" ECM is - A junkyard pull thats been repainted, had a new sticker slapped on the case, and new capacitors (sometimes).

Sometimes the only thing new is the box.

That's why I was wary of all the 'refurbished' fuel injectors on Ebay and Amazon. I think once the IAC and TPS are replaced it will be much easier to determine if the computer has a problem