Chris Boots

Hey do you think if Pin 3B on the ECU was not working it would start like this? Can I just jump it to the starter soliniod wire to test it?

Chris Boots

Oh and TehMonkay, The injectors are brand New. I got them just for this engine. So I know they aren't leaking. Thanks for the reply

HAILERS

No. 3B is not the problem. If that pin was NOT seeing 12v when you held the key to Start, then your problem would be difficult starting when the engine was cold BUT normal starting when the engine was hot. Problem is not with 3B (start signal TO the ECU).


Just to clear things up, you do not have the emissions items on the engine. Right? Like no ACV, airpump etc?

The hot engine non start does sound like low compression. New rebuild. Might need a couple thousand miles to settle in so to speak.

Here is an idea but it takes a very small bit of talent. You need to know how to remove a wire from a ECU connector. You do that by removing the plug from the ECU. Then with something like a very small jewelers common screwdriver, push down on the locking tab in the socket for the wire to be removed and then pull the wire out.

I'm talking about going to pin 3B and extracting that wire when the engine is HOT. Now with the wire extracted and engine HOT, go drive it for a while.........stop the engine........start the car........drive.......stop the engine........start the engine.

If you find that the engine starts each time when HOT with that wire out.........I'd say low compression is the problem right now. If this is the case, you could make a temporary switch for pin 3B. You'd only have to use it once a day. That would be for the cold starts, not the hot starts.

What the removal of 3B does, is make the ECU use the AFM signal for fuel duing the starts and NOT the internal ECU Start map. I'll post a jpg later of that. In other words a leaner fuel mixture duing START and only Start if that pin is removed.

After a few thousand miles things might improve on the compression.

This post does not address your problem accelerating at three grand etc.

Chris Boots

Hey good Idea. I'll de-pin it and see what happens. If that woks I'll probably just end up wiring it to a switch that I'll put right next to Fuel Cut switch. I'm searching like mad to find the stutter at 3000+

HAILERS

Right around 3000rpm. Not 3500-3800rpm? That's the way I read that so it isn't secondarys coming online.

On a series four the ECU gnds are on a ring terminal bolted to the top of the rear rotor housing. Can't seem 'em unless the intake is off.

Hmmmm. It might have something to do with the secondary throttle plates. If stock, their linkage rides on a CAM, black in color and also rides on a mushroom shaped damper that looks similar to the Dashpot. The 3000rpm might be the point where the secondary throttle plates start to open. This is just a guess.

A jpg of the Front of the throttle body supplies. A little dark but if you look at Your throttle body it makes sense when you look at the attached jpg.

And yes. You could rig a temp switch off 3B for a few thousand miles til things settle down. If you have old harnesses laying about with that same small ECU plug, you could depin That wire on that old harness and cut the wire several inches back. Then install That piece of wire with its terminal, into your cars small ECU plug.

Then have the cut end of that piece of wire go to a switch and the other terminal on the Switch go to the cars wire that would normally be in 3B on the ECU. Make sense.

HAILERS

Sooner or later someone is going to suggest doing the throttle body mod. Well, you can simulate this Modification to see if you really like it or not. Look at the jpg attached. You remove the spring and rod I point to in the jpg and put it on the shelf. There's just a small 8mm nut and one cotter pin holding that to the throttle linkage. Remove it and put it away for later use.

Then wire tie the linkage it was attached to, to the open position. Even a tie wrap would do that instead of wire. That way the outer secondary throttle plates are open allllll the time.

I'm curious. Does the jpg show up large enough to look at on your computer?

Chris Boots

It hessitates bad from 3000+. I'm looking at your pics (which are big enough btw) and I remember I don't have a vacuum line going to the diafram right next to the dashpot looking thing. When vacuum is applied to the diafram it pulls a rod. Does this need to be connected?

HAILERS

No. That is the Double Throttle Diaphrams hose. The hose goes back to the water thermo Valve (plastic, two plastic nipples). And the other nipple on the water thermo valve goes to the BOTTOM metal nipple on the back of the throttle body. There's three or on some cars four metal nipples there. Only one is vacuum, the bottom one and it goes to the water thermo valve as described. I have a hose but it's not functional. The diaphram in the double throttle is busted so the metal nipple on the bottom of the throttle body is blocked off. Not your problem.

Hesitates bad. Almost sounds like a pressure/boost sensor problem. It would help if you went to pin 2B (brown/red wire) and with the connectors all on their places, backprobe the 2B with the key to ON and read the voltage. Engine OFF, key ON. I'm wondering if that really is a turbo boost sensor.

In fact you really NEED to do this to 2B.

Idle the engine hot. Pull the vacuum hose off the boost sensor. Feel for vacuum on the hose. Is vacuum there?

Chris Boots

Well not so good news man. I went to start it up today and there is no cold start system working. I have to start it as if it was warm. It starts up and drops down to 750 COLD. It doesn't idle up to 1250 or even shoot up to 3000 when I first crank on it. I know now the compression isn't to blame cause there's no way an engine with lower compression is going to idle at 750 when its cold and 40 degrees out. I check the thermo pellet and it goes up as it gets hotter but the rod doesn't do anything. I turned the screw all the way clock wise when I just started it cold: (no difference). I turned it all the way counter clockwise and still no difference. So I know thats a damn problem I have to figure out now. Maybe it really is that 3B wire? I think I solved the 3000 stutter... I still have to check it but I found that the main ground wire that goes to the boost sensor was not grounded or anything. Oh and I put a different ECU in it (N333) and same problem so its not the ECU

TehMonkay

iTrader: (-1)

Man, i would just take a DMM to the whole harness, that may be your problem, a bad harness. Check resistance and everything.

You do have the correct impedance injectors, right?

What year is the harness? 86-87 or 87.5-88?

satch

iTrader: (1)

[QUOTE=Chris Boots;7872675]It doesn't idle up to 1250 or even shoot up to 3000 when I first crank on it.


The reving to 3000 on a cold start is designed to only occur when the temp in the radiator is around 60 degrees and above or so and not below. Since it is cold where you are it will then not rev to the 3000 mark on a cold start but is supposed to fall short of that number to around 1500 rpm.

Chris Boots

Tehmonkay: I'm so close to printing off the pages in the FSM that describe what every wire going to the ECU should be and function at and testing every one. In fact I think thats what I'll do tomorrow if I have the time. Oh and its a 09 of 1988 harness so its in the 87.5-88 range you were talking about. And they're definately the right injector imp.

satch: the sensor that triggers the 3000 rpm (60+ degress) I jumped to see if it would make a difference and nothing happened. But ya, like I said it doesn't idle anywhere above 800. It just starts and drops down to 750-600 and stays there perfectly with no stutters or anything... Which is amazing for a new engine and this cold weather. As you can see this car is becoming a bit of a problem child...

HAILERS

The 3000rpm is an Electrical function of the BAC working with the Air Bypass Solenoid. And like Satch said happens when the water is b/t something like 60* and 90*.

Maybe I made a mistake saying to jumoer the two bullet connectors for the Water temp switch below the radiator. I'll look into that later.

That admission made, I remember another thing I messed up on. The Air Bypass Solenoid is located on the top of the turbo engine. But on the non turbo it's located on the left rear side of the engine. The electrical leads for the Air Bypass Solenoid would have to be lengthened to reach from the left rear side to the top of the engine. Frankly that Air Bypass Solenoid only works for 17 seconds during a cold start to drive the rpm to 3000rpm. IF that item is not connected up, then the BAC still drives the rpms up, but without the Air Bypass Solenoid being there, the rpms will only go to approx 2000rpm, then drop to approx 1500rpm if the waterthermowax, fast idle cam etc is set right.

In other words the cold engine idling at 1500rpm and gradually dropping down to 750 is a purely Mechanical function. I'd recommend pulling the throttle body and setting the fast idle cam/waterthermowax etc per the FSM. Like I said, THAT is a purely Mechanical function. NO electrics involved in the 1500rpm idle cold and dropping down to 750rpm once warm.

Odd. Most people don't like the 3000rpm's for 17seconds on a cold engine, a function of the Air Bypass Solenoid (called AWS on series five, same item).

About the water thermowax and the screw who's bottom sits on top of that piston. IF you screw that screw all the way clockwise and bottom the screw out, then that will cause the cam/roller to seperate earlier or forever and there will be no high idle at approx 1500rpm when the engine is cold. Turning it anti clockwise will do the opposite. The cam/roller will seperate later and if too far anti clockwise it might never seperate resulting in a high idle all the time.

I threw in a couple of jpgs of a old throttle body showing the thermowax piston with screw sitting on it and a jpg out of the FSM.

HAILERS

As far as checking the electrical, what you want to do is go to the pages called Control Unit in the FSM fuel section. It lists each wire on the ECU and what each one should read when at idle or just the key to ON.

Pages like the one that is attached. That page is for a Non Turbo car.

Like I mentioned in a post above about the hesitation, look at pin 2B, the boost sensor output and compare it with the manuals value to see if there's a problem there.

HAILERS

Just talking about the high rpms upon start.............go to the Fuel and Emissions Training Manual that is free and online. Go to page 4-55 and it's explained there.

The water thermo sensor is the key player, not the water temp switch in the bottoom of the radiator (I'd leave that jumpered, what with your broken sensor).

The temperature for that high rpms to happen is b/t 59* and 98*F. Won't happen below those figures and won't happen above.

But you should still get the 1500rpms for a cold engine at idle til the thermowax gets hot. See the same manual mentioned above for the water thermowax.

During those temps 59-98*F, the BAC drives the rpms up to about 2000rpm by itself, and if the Air Bypass Solenoid is also in the system, the rpms will go to approx 3000rpm for 17 seconds. A jpg of where the Air Bypass Solenoid is attached. You'd have to extend the present wires on the n/a harness to its new location.

arghx

iTrader: (3)

can you post these pics? Now, at the risk of hijacking this thread....

I am still having a hell of a time getting my thermowax to work properly. I went through the FSM and attempted to set it, but the clearances are very difficult to measure even with a feeler gauge so I may have screwed it up. I tried to do it under the proper temperature (75 degrees?) but maybe it wasn't close enough. Now I want to just fiddle with it on the car to see if I can get better results.

I know there is the throttle stop screw (with the 8mm nut) and the screw that touches the piston for the thermowax. Something must be messed up... currently the car has a cold idle of about 900, and a warm idle of 1100 or so... this is with no BAC. The roller separates fine, but I guess it's separating too early from a misadjusted screw?

Should I turn the thermowax piston screw counterclockwise to raise the cold idle, then turn the throttle stop screw slightly counterclockwise to set the warm idle?

Chris Boots

Well hailers your right about most people not liking the AWS and I'm one of them. It was more the fact that it wouldn't even idle up to 2000 and drop down to 1500 like it should. So I have worked on the thermo wax for a long time and found out that its probably broken. The thermo wax comes up when its warm but it makes no difference in the idle speed. I moved the screw all over the place and there wasn't ever any difference, I even took the screw out once when it was cold but it still had the same problem so... I'm going to get another throttle assembly and use that one.
I did have to lengthen the wires to the ABS but my intake looks nothing like the one in your picture. My BAC is a little bit higher up than yours, there is no hose or inlet above my BAC. I don't have an ABS in the same place yours is (mine is on the back of the intake right next to where the throttle cable braket is. And I have an Idle screw on mine that isn't in the BAC. So This is definately a J-spec intake.
I boosted it for the first time today (mainly because it won't stutter if you floor it) and I watched my gauge. I hardly got 2 psi of boost. It should be like 7.5. My friend seems to think that the Knock sensor not being hooked up has to do with it. As far as the ECU knows there is no knock sensor on this car. So I think something else is wrong with that.
You were right about seeing if it will start warm when I disconnect the 3B wire... It will start way better. I don't even have to cut the fuel.

HAILERS

Nope. On the back of the throttle body, there is a solenoid. But that solenoid is the Air Supply Solenoid and is a power steering related item. Move power steering at idle and the solenoid opens a bit to compensate for the extra load. No pwr Steering? Remove it and plug the small hole it was covering. Also plug the hose coming off the back of the intercooler.

That picture I stole off the internet, not my car.

Knock sensor has zip to do with your lack of boost. I have no knock sensor connected up on either of my cars and boost 10psi on a daily basis. The knock sensor if connected up and seeing knock would retard the ignition. And you don't have the knock box nor the knock sensor connected to anything (at least that wire should not be connected to anything right now, what with no knock box).

Good about 3B. Make a switch. You won't need the fuel cut switch anymore or rarely. I think if the engine gets broken in the compression will go up and things will improve.

Low boost can be caused by a clogged converter/exhaust.

I'm not familiar enough with JSPEC engines to know if they should have a Air Bypass Solenoid as shown in my picture or not. I've nothing really against them working but I don't think it's worth your time and effort to lengthen the wires from the left side of the engine to the top of the intake.

If you have no pwr steering, I'd remove that Air Supply Valve/solenoid. It's easier to reach behind the throttle body to mess with hoses if that thing is not there.

2psi .......not good. Don't know what to say about that. Hopefully it's a clogged exhaust system.

Chris Boots

Well this has power steering in it so I'll have to figure that out. I'll make a switch for it probably tomorrow. There is only one Cat left on this car right now. (the one that has an emissions line going to it) I blocked that line and left the cat alone. I had a down pipe made to adapt to that system cause it was all brand new underneath. Except for the cat, I don't know how old it is. How much more loud will it be if I remove the last cat? I don't want it too loud cause I didn't exactly build this car to be an all out fast and loud rotary but more of a stock looking, sounding sleeper. There is no hint to there being a Turbo engine in this. Stock hood and everything.

I've been looking at that your pics and I see that I don't have a dash pot (no problem) I don't have and EGR (all blocked off with the rest of the emissions crap), The "to intercooler is hooked up to an other hole of the same size right next to the BAC, and the rest looks pretty much the same. So I'll try and get another throttle body tomorrow and see what happens. Technically that should fix the cold start problems I'm having and maybe things will work better all together. Here's an Idea... that cat wouldn't have an effect on why it stutters at 3000+ would it. Cause it will accelerate fine (up to 2 psi of boost (damn it) if I floor it. I've driven many a Turbo 7's and they pull way more than this one does with out even giving it half throttle...

rxsevn89

Just so you know we are at 3000ft so 65 to 90 psi is ok. And yes the injectors have been cleaned and checked

rxsevn89

Chris he might be right The cat could be alittle clogged. That would defi. cause a problem and that would also cause the dying when we would rev. in the shop that day. the last one that I saw with a bad cat was acting similar to this. Call me tom. and we will get a diferent throttle body.

HAILERS

Since you DO have pwr steering, you NEED to remove pin 1R from the ECU. On the Turbo ECU 1R is for the knock sensor. On non turbo that wire gets a gnd put on it when the steering wheel is turned. Not desireable on you car.

I had/have no pwr steering so for a long time I did nothing with 1R, until once when I installed a knock box (since removed). So I've never experienced what will happen if a gnd is put on that wire on the Turbo ECU. Should retard the timing a bit if a gnd is put on that wire. I think. Don't Know that. I'd just depin that wire for now.

It won't really effect your pwr steering that much. It was only for Idling up so to speak, when the wheel is turned while the car isn't moving. Give it a go. Extract that wire 1R.

HAILERS

The two psi and crummy above 3000rpm could also be a symptom of the outer seconday throttle plates not opening. I made mention of this earlier and attached a jpg of the cam/damper the secondary linkage that controls the outer set of plates.

So. Remove the rod/spring/cotter key I showed in that jpg and hold the outer plate linkage fully open with a piece of wire/whatever and go for a drive.

HAILERS

About the water thermowax......................I assume you've been adjusting the cam adjusting screw with no results. So look at my jpg and see if you've tried to adjust the fast idle screw or not. You might give that a try one way or the other. It's difficult to see that screw on the throttle body. Look for it.

Or someone might have the throttle stop screw screwed so far out that, that is the culprit. You might just loosen its 8mm jamnut and back that screw off where it does not touch the linkage and then try the cam adjusting screw again.

BUT, I'm serious about my post above this one that addresses the outer set of secondary throttle plates. That might very well be why your seeing only 2psi.

arghx

iTrader: (3)

^ What's really thrown me for a loop is that it idles HIGHER with the car is warm (1100 warm, 900 cold). Since it idles around 900 (which is actually around where i'd like it right now) when cold, that says to me that the stop screw is set ok. Because if it weren't, it would hold the primary throttle plates open too far for the idle to get that low. So if my logic is correct, that leaves me with the fast idle screw and the cam adjusting screw to play with. I really thought I had the cam adjusting screw set to spec. I lined up the mark as best as I could, according to the FSM. I had the TB sitting in my house at a temperature somewhere in the 70 degree range, and I lined up the mark.

I have not messed with the fast idle screw though. Should I tighten (clockwise) it? Does that increase the idle speed?

I guess you could say I'm trying to figure out how all these three screws work together so I can understand the system and get it working correctly. Just like when you are tuning an EMS, you need to know what to adjust and in what order.

So the stop screw controls how high the idle can be when fully warmed up? Then the fast idle adjusting screw controls how high the idle is when the thermowax is fully cold? And then the cam adjusting screw controls the transition from fully cold to fully warm? I know according to the training manual that the idle is supposed to decrease in a couple discrete steps, like from 1500 to 1200 to maybe 900 to 750, all mechanically through the fast idle system.

Maybe nobody has figured out exactly how all those adjustment screws work together. I bought my car with a throttlebody out of adjustment, and then I bought a used one that was unfortunately way out of spec as well, so I need to figure this out as best I can. I'm convinced this is a mechanical problem with my TB because I have zero vacuum leaks (pressure tested) and no BAC valve or anything else that would affect idle.