Idle Adjustment Issues 2.3 Turbo fuel injectedto

JCullen

Member
Jan 2, 2020
55
5
8
74
Indiana
About three weeks ago my 87 2.3 Turbo would die at a stop sign. It started this all in a moment. From running great to trying to keep it going at idle or just above.
When I got home I found the coupler that wires the idle air by-pass solenoid had come off. I hooked it back up but that did not solve the issue. I replaced the solenoid since it was old. Still no progress.
I checked the voltage from the ECU to the throttle position the sensor and was able to get it to stabilize at .9 volts with key on and engine not running. But still, when I would start it it would not idle. I adjusted the idle set screw in until the spring was compressed all the way. This did allow the engine to stay running but below normal idle speed.
There are 5 volts going to the input terminal of the throttle position sensor with .9 volts on the middle terminal.
It is my understanding one should not have to adjust the idle set screw from factory setting. Is this correct?
My timing is set at 10 degrees BTDC with the spout removed.

Any suggestions where I should look next to resolve this idle issue?
 
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junkyardwarrior

Active Member
Jan 10, 2011
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start the engine, go drive around a while for the engine to get up to operating temp. If it's hot out like it is here (100+) it won't take long, 5 min maybe. When you get back home, shut it off. Unplug the spout. Unplug the IAC. Then start the engine and let it run about a minute or so. Your idle speed should be about 750-800 at the most with the spout out and IAC disconnected. If you can't achieve that, you have some other problem. If you can, shut the engine off, then disconnect the battery, reconnect IAC and SPOUT. Leave the battery disconnected for about 15-30 minutes while you go have a glass of tea. When you come back out, reconnect battery and then start the engine at an idle only, and let it sit & idle for 10 min or so, if it will. If it won't you have other issues. Perhaps a vacuum or air leak somewhere.

Speaking of vacuum leaks, it would be wise to check for vac leaks and air leaks between the VAM and turbo. Any leak will throw everything off, it will run rich if you have a vacuum leak and lean if you have an air leak between the vam and turbo.

Right you shouldnt really ever have to adjust the throttle stop screw under ideal conditions.

Also carbon buildup behind the throttle plate in the throttle body will cause reduced airflow through the throttle body. Might look at that. A lot of times you will see a large ring of carbon once you open the throttle plate (engine off of course and intercooler tubing removed so that you can visually SEE the throttle plate). Most 2.3 TB's have a bleed hole in the throttle plate and over time it will carbon up, closed, and also reduce air flow through it. Worth looking at that too. Cleaning it is easy. Remove it from the intake manifold and use an old toothbrush and some mineral spirits combined with patience to clean it. Don't use a wire brush, it's too aggressive. I've never had one that a toothbrush and spirits wouldn't clean up to look almost brand new. Similarly, the IAC will also sometimes get carbon'd up and will need cleaning. The large end (opposite the solenoid/connector) has a ring around the outside of it, you can grind the ring off, and once it's off you can use a flat blade screwdriver and remove the cap by unscrewing it, then remove the plunger noting how it came apart, remove the solenoid, and clean the body of the IAC and the plunger up real well, spirits and a toothbrush work well. Dry it out, reassemble. It makes a big difference in how it runs/idles because the IAC is also responsible for dashpot among other things. Once you do those two (if needed) reassemble them to the engine and then re-test for vacuum leaks. I like to use a piece of PVC with a vacuum/boost gauge in it, and a nipple with a ball valve that hooks to an air hose to pressurize the entire intake system. 10-15 psi is all you need. At that point any leaks are obvious, particularly if you are using soapy water to locate them. Expect the throttle shaft seals to leak, they all do, and it doesn't make a "big" difference if they are sealed up. It does help but it's not night & day and they run fine with them leaking a little.

That outta keep you busy for a while....let us know how goes it.
 
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JCullen

Member
Jan 2, 2020
55
5
8
74
Indiana
start the engine, go drive around a while for the engine to get up to operating temp. If it's hot out like it is here (100+) it won't take long, 5 min maybe. When you get back home, shut it off. Unplug the spout. Unplug the IAC. Then start the engine and let it run about a minute or so. Your idle speed should be about 750-800 at the most with the spout out and IAC disconnected. If you can't achieve that, you have some other problem. If you can, shut the engine off, then disconnect the battery, reconnect IAC and SPOUT. Leave the battery disconnected for about 15-30 minutes while you go have a glass of tea. When you come back out, reconnect battery and then start the engine at an idle only, and let it sit & idle for 10 min or so, if it will. If it won't you have other issues. Perhaps a vacuum or air leak somewhere.

Speaking of vacuum leaks, it would be wise to check for vac leaks and air leaks between the VAM and turbo. Any leak will throw everything off, it will run rich if you have a vacuum leak and lean if you have an air leak between the vam and turbo.

Right you shouldnt really ever have to adjust the throttle stop screw under ideal conditions.

Also carbon buildup behind the throttle plate in the throttle body will cause reduced airflow through the throttle body. Might look at that. A lot of times you will see a large ring of carbon once you open the throttle plate (engine off of course and intercooler tubing removed so that you can visually SEE the throttle plate). Most 2.3 TB's have a bleed hole in the throttle plate and over time it will carbon up, closed, and also reduce air flow through it. Worth looking at that too. Cleaning it is easy. Remove it from the intake manifold and use an old toothbrush and some mineral spirits combined with patience to clean it. Don't use a wire brush, it's too aggressive. I've never had one that a toothbrush and spirits wouldn't clean up to look almost brand new. Similarly, the IAC will also sometimes get carbon'd up and will need cleaning. The large end (opposite the solenoid/connector) has a ring around the outside of it, you can grind the ring off, and once it's off you can use a flat blade screwdriver and remove the cap by unscrewing it, then remove the plunger noting how it came apart, remove the solenoid, and clean the body of the IAC and the plunger up real well, spirits and a toothbrush work well. Dry it out, reassemble. It makes a big difference in how it runs/idles because the IAC is also responsible for dashpot among other things. Once you do those two (if needed) reassemble them to the engine and then re-test for vacuum leaks. I like to use a piece of PVC with a vacuum/boost gauge in it, and a nipple with a ball valve that hooks to an air hose to pressurize the entire intake system. 10-15 psi is all you need. At that point any leaks are obvious, particularly if you are using soapy water to locate them. Expect the throttle shaft seals to leak, they all do, and it doesn't make a "big" difference if they are sealed up. It does help but it's not night & day and they run fine with them leaking a little.

That outta keep you busy for a while....let us know how goes it.
 

JCullen

Member
Jan 2, 2020
55
5
8
74
Indiana
I shot a bit of carb cleaner around all the intake tubing etc and no increase in rpm. Then I sprayed a shot around the pcv hookups and the rpms went up. I corrected that possible leak but the engine still will not idle. I get it to start great and run above 1500 rpm. It will run there for a few minutes. When I try to reduce the 1500 idle speed it immediately drops right past 1000 rpm and to dead stop.

I have tried using 2 new throttle position sensors and a new idle air by-pass solenoid to no avail. I don’t seem to find any other leaks.

This all started one evening when I came to a stop sign and the idle fell to stop the engine. Every time I would then shift and let off the accelerator, it would die. When I got home I found the coupler that wired the idle air by-pass solenoid had come disconnected. That was all that seemed to cause my issues.

I read one thread where it can take the ECU up to 75 miles to rest itself. Is this true? And if so , I don’t think I will enjoy trying to drive Frankenstein 75 miles when it dies below 1500 rpm.
 

JCullen

Member
Jan 2, 2020
55
5
8
74
Indiana
I shot a bit of carb cleaner around all the intake tubing etc and no increase in rpm. Then I sprayed a shot around the pcv hookups and the rpms went up. I corrected that possible leak but the engine still will not idle. I get it to start great and run above 1500 rpm. It will run there for a few minutes. When I try to reduce the 1500 idle speed it immediately drops right past 1000 rpm and to dead stop.

I have tried using 2 new throttle position sensors and a new idle air by-pass solenoid to no avail. I don’t seem to find any other leaks.

This all started one evening when I came to a stop sign and the idle fell to stop the engine. Every time I would then shift and let off the accelerator, it would die. When I got home I found the coupler that wired the idle air by-pass solenoid had come disconnected. That was all that seemed to cause my issues.

I read one thread where it can take the ECU up to 75 miles to rest itself. Is this true? And if so , I don’t think I will enjoy trying to drive Frankenstein 75 miles when it dies below 1500 rpm.
This vehicle ran great up to the minute the idle air by-pass connector came off.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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polk county florida
Have you done a computer reset?
Disconnect the battery for 15-20 minutes, hook it back up and drive it around for a while, get the engine up to operating temp then check for codes.
 

JCullen

Member
Jan 2, 2020
55
5
8
74
Indiana
I drove the vehicle this morning and I can now get it to idle but not very smooth.

I will disconnect the battery even though the total power system is isolated from the battery when the key is off.
 

junkyardwarrior

Active Member
Jan 10, 2011
324
76
48
you really need to do a better job of isolating vacuum leaks. spraying flammable substances on a hot engine is not the correct way to do it nor is it accurate. You need to do a pressure test on it and use soapy water around all of the connections that may be a source. In doing this you'll find leaks-lots of them most likely.

The other way to do it is with a smoke machine which you can make or you can buy inexpensively.

My brother's face is mostly unrecognizable due to him trying to find a vacuum leak using carb cleaner. It ignited while he was checking for leaks on a 78 F100.

is there a possibility that the cam timing is off?
 
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JCullen

Member
Jan 2, 2020
55
5
8
74
Indiana
I found the problem.
This 85 Turbocoupe engine is in a 1929 Ford pickup. When I bought the engine it had no auxiliary systems on it. Since this was my first experience of using a turbo and the fact that this vehicle is put together with parts from so many different cars, it is difficult to trace a problem. I used a forum idea to find it. Someone mentioned a leak between the mass air flow sensor and the plenum. After checking the mass air flow, I started taking some sticky back heat reflective material off of the hoses that go from the intercooler and the plenum to check that possibility. I immediately saw that the coupling between intercooler hose and the plenum hose had become distorted by heat and had eventually allowed the reducing silicone hose to slip partly off the pvc coupling. It all made perfect sense why the truck would run up from showing a strong vacuum to “0” on the gauge but would then fall flat upon further acceleration and never show a positive bpost.

I found that the 85 never had an intercooler, nor an air intake temperature sensor. I had purchased an 85 rebuilt ECU but it would not run well on that unit. So I plugged in an old 87 ECU I salvaged from a Turbocouple that had been sitting in a woods for 25 to 30 years. And the engine ran great. I found a small aluminum intercooler and adapted it to fit and had a screw in port put in it for the intake temp sensor. I was also using an 87 mass air flow from the salvage 87. So I have an 85 base engine with most other systems being from 87 Mustang, T-bird. It runs through a Mustang 5 speed transmission to a Mazda NA differential, Mazda 4 wheel independent suspension with coil overs. Frankenstein, as I call it, uses Mazda Miata rack and pinion power steering and 4 wheel power disc brakes.
But the old Ford is back to having Ford power.

I really appreciate all of your input and help. I am an old 74 year old that still enjoys learning new things and all of your posts have contributed to me learning more about my creation.
Thanks again and I will most likely ask for help again sometime.

By the way, this little pickup is scary fast.
 

JCullen

Member
Jan 2, 2020
55
5
8
74
Indiana
Photos taken recently.
 

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junkyardwarrior

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Jan 10, 2011
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you can make a pressure tester for the system really easy.

Grab a piece of PVC pipe and some flexible couplings to mate one end of the pipe to your turbo inlet. The other end of the pvc will be capped, and will have a gauge, and a 1/4" ball valve with an air hose fitting in the ball valve inlet. The assembly will be screwed into the cap next to the pressure gauge. Attach the open end with flexible coupling to your turbo inlet and tighten the daylights out of the clamp. You'd have to remove the crankcase vent tube or you'll also pressurize the crankcase. Once you're set, pressurize the turbo/intake with about 15 psi max. You can go higher & lower if you wish but 12-15 is fine. Grab your spray bottle of soapy water and spray around all of your intake components, turbo to back plate, vacuum hoses/lines/tubes, upper intake, throttle body areas, etc etc. When you find a leak, note it on a piece of scrap paper, because there's usually multiple. Then remove the pressure, and fix all your air leaks, re-test, repeat until you get them all fixed. Once all the vacuum/pressure leaks are fixed, you'll find that the engine runs a lot better.

I use a 90 deg elbow 2" pvc setup (I think it's 2", I forget), and the elbow makes it easier to get onto the turbo behind the a/c lines on my car. I also use it on the truck (turbo diesel) and have used it on the 92 GT to find vacuum leaks. I found all kinds of leaks on the truck. Repairing them made a huge difference mostly under part throttle. It's actually rare that I ever get to full throttle with the truck nowadays even pulling. They work great and are very inexpensive to make/build.

If/when you do have a leak, what can happen is a lot of things, one as the turbo spins up, it's sucking through the vam (some call it a MAF but it's not a MAF, it's a vane airflow meter) opens the vam "door" (vane), and the ecu thinks that the engine is under a load, starts dumping fuel and the engine falls on it's face. Secondly, with a big boost leak the turbo can overspeed because there is no pressure building in the system to open up the wastegate. If you have a leak between the vam and turbo, the engine goes LEAN, usually resulting in head gasket failure or worse yet broken/bent rods, etc.

85's did have intercoolers but only on SVO. 84, 85, 85.5, and 86 svo all were intercooled. Thunderbirds didn't get intercoolers til 87, and they had tiny turbo's. Merkurs never had intercoolers. Cougars didn't either to my knowledge.

Neat truck. I've seen 2.3T's in about everything now.
 
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JCullen

Member
Jan 2, 2020
55
5
8
74
Indiana
you can make a pressure tester for the system really easy.

Grab a piece of PVC pipe and some flexible couplings to mate one end of the pipe to your turbo inlet. The other end of the pvc will be capped, and will have a gauge, and a 1/4" ball valve with an air hose fitting in the ball valve inlet. The assembly will be screwed into the cap next to the pressure gauge. Attach the open end with flexible coupling to your turbo inlet and tighten the daylights out of the clamp. You'd have to remove the crankcase vent tube or you'll also pressurize the crankcase. Once you're set, pressurize the turbo/intake with about 15 psi max. You can go higher & lower if you wish but 12-15 is fine. Grab your spray bottle of soapy water and spray around all of your intake components, turbo to back plate, vacuum hoses/lines/tubes, upper intake, throttle body areas, etc etc. When you find a leak, note it on a piece of scrap paper, because there's usually multiple. Then remove the pressure, and fix all your air leaks, re-test, repeat until you get them all fixed. Once all the vacuum/pressure leaks are fixed, you'll find that the engine runs a lot better.

I use a 90 deg elbow 2" pvc setup (I think it's 2", I forget), and the elbow makes it easier to get onto the turbo behind the a/c lines on my car. I also use it on the truck (turbo diesel) and have used it on the 92 GT to find vacuum leaks. I found all kinds of leaks on the truck. Repairing them made a huge difference mostly under part throttle. It's actually rare that I ever get to full throttle with the truck nowadays even pulling. They work great and are very inexpensive to make/build.

If/when you do have a leak, what can happen is a lot of things, one as the turbo spins up, it's sucking through the vam (some call it a MAF but it's not a MAF, it's a vane airflow meter) opens the vam "door" (vane), and the ecu thinks that the engine is under a load, starts dumping fuel and the engine falls on it's face. Secondly, with a big boost leak the turbo can overspeed because there is no pressure building in the system to open up the wastegate. If you have a leak between the vam and turbo, the engine goes LEAN, usually resulting in head gasket failure or worse yet broken/bent rods, etc.

85's did have intercoolers but only on SVO. 84, 85, 85.5, and 86 svo all were intercooled. Thunderbirds didn't get intercoolers til 87, and they had tiny turbo's. Merkurs never had intercoolers. Cougars didn't either to my knowledge.

Neat truck. I've seen 2.3T's in about everything now.