easy p-cheesy

OK, here's the deal. I have a 91 TII with a Microtech on it. Stock ports, stock turbo, all it has is intake, and exhaust, 720cc secondaries, and a walbro fuel pump. Boost has been set to 9 PSI. The MicroTech was installed to the car 2 owners ago. It was tuned by Rotary Performance (by Chris) and this is one of the few Microtechs he has tuned.

Basically what happened was I took the UIM off to work on the TB (it had been sticking). It had already had the TB mod done aside from the removal of the fast-idle cam. I took that off and put the UIM back on. (keep in mind, it was running fine before the UIM was off) When I tried to start it, it didn't want to hold an idle, the engine would vibrate a decent amount, it was dumping mass amounts of smoke out of the exhaust, and was misfiring. I could keep it running at pretty much any RPM but it wouldn't idle if I let off. I tried driving it like that, and it seemed almost fine at close to atmospheric vacuum, but if I let it get low it'd buck, and I could not get into any form of boost, and it'd buck if I tried.

I had a friend help me, and we ended up cleaning up the wiring. What we found was that the water temp sensor wiring had a bad connector on it and the ECU was not getting signal (it put it at 0ēC). Anyway, we finished up the wiring and checked it many times and everything is wired up as it should be. The water temp sensor is getting signal. The trailing coils are not firing and there is no tach bounce on the stock tach (I have checked the wiring probably 10 times). There was an RPM error and the CAS ended up having a chip in it. I put another CAS in and it's working now, but the problem is it wont start. It will fire a few times. Right now it seems like a timing issue, but the closest I've been able to get it with timing is a couple of fires and maybe running a tiny bit.

A few other things:
-I'm pretty sure there were vac leaks BEFORE I took it off (mainly the AWS nipple on the IC)
-the ASV was attached and the line to the IC was attached, and the microtech was tuned somewhat to use it, but the ground line on it was not hooked up and from everyone I've talked to (both previous owners) the tuning of using the ASV as idle control for AC was never completed so it wasn't used.

Anyone have any ideas?

Radial GT

iTrader: (16)

Lean it out. Are you in matrix mode? You probley loosened the throttle cable more than it was before.

Infini IV

1) Check over your wiring (once more) and be sure it matches with the Microtech diagram (included in the manual).
2) Stab the CAS in properly again (just to be sure)
3) Reset TPS! (don't forget!)
4) Lock timing with timing light
5) If the ASV was never used, then might as well get rid of it at least until you can get the car running right.

Do those in order and see if it'll get things working.

easy p-cheesy

I don't really want to mess with the fuel maps because the car has already been tuned by Rotary Performance. It was running fine before, so these maps should work once the timing is all figured out and any other problems are fixed. Yes, I'm in matrix mode. Every time I've taken the UIM off, I've reset the TPS calibration, so this isn't the problem.

1) Check over your wiring (once more) and be sure it matches with the Microtech diagram (included in the manual).
-I have many times, and it is wired up exactly as it was before the UIM came off. All that was really done was re-routed a lot of stuff, redid some solder points, and loomed it all up.

2) Stab the CAS in properly again (just to be sure)
-Ok, I was planning on it.

3) Reset TPS! (don't forget!)
-I've been reseting it every time I take the UIM off.

4) Lock timing with timing light
-I've been having trouble getting the timing light to work. Does it need to run for it to do so? Are there any specific ways I should be doing this (hooks up to L1, right?) It's a pretty cheap light with no advance/retard adjustment, but it should work.

5) If the ASV was never used, then might as well get rid of it at least until you can get the car running right.
-It is blocked off for now.

What else...
I am now remembering that I haven't seen the MAP sensor reading anything other than 02hg. I have a new line on there, but who knows, maybe it got messed up somehow. I'll check that tomorrow to see if it's a problem with the line.

Infini IV

Where is your vacuum line hooked up to in the UIM? The best place should be the lowest nipple on the front of the UIM (side facing the alternator).

Now reading over your first post again, it sounds like your timing is just off. And yes, hook the timing light up to L1.

Are you getting anymore sensor errors since fixing the important ones (water temp, CAS, TPS, MAP)?

Radial GT

iTrader: (16)

I thought the microtech took care of the timing? I can turn my CAS and it has no effect on the engine.

Your MAP should be changing anytime you hit the gas.

Even though your computer was tuned by someone, it doesn't mean that you will never have to touch it. There is a slight bit of adjustments through the year that must be performed to keep it running smooth. One down fall with aftermarket computers. You can have someone tune it for you, but eventually you do have to learn how to tune it smooth on your own. Save your currect map as a reference, and start learning!

Infini IV

Microtech will allow you to adjust timing, but it is directly related to the CAS.

I don't believe that you have to do any adjustments at any time during the year to keep it running smooth. Assuming you have someone tune it who understands how factors such as atmospheric pressure, climate, etc. tune it, and don't keep installing performance parts, then one complete tuning session should do good. Your computer should not just get out of alignment wiht time.

easy p-cheesy

-The map line is hooked up to the lower nipple on the front of the UIM. All of the vacuum lines are hooked up as they were before removed.

-The timing light is hooked up to L1 and we're not getting any flash.

-I'm not getting any error codes now. The Vacuum/boost gauge on the MicroTech did turn red once, but only once.

-The first chance I get, I'm checking the MAP sensor.

- The EMS may need slight adjustments yearly if it wan't tuned well enough to deal with climate changes. Anyway, the weather is relatively close to the way it was when I bought the car and even these changes shouldn't have made that much of a difference to make it that rich.

Infini IV

If your timing light is bust, have a friend turn the CAS while you crank it. Be careful and turn it slowly though. As long as you stabbed it within range, turning it a bit should get it good enough to start. Do you have a laptop or a HC from which you are able to give us the T_RPM and T_MAP values? You might also want to try matching your idle map with the base-from-Microtech maps which are posted by silverrotor. If anything, just re-tune the idle map.

easy p-cheesy

I hope it's not bust, I just bought it.

t_map
30hg = +10
25hg = +08
20hg = +06
15hg = +04
10hg = +02
5hg = 0
0hg = 0
2psi = 0
4psi = 0
8psi = -02
10psi = -03
14psi = -10
16psi = -20
18psi = -15
20psi = -20

t_rpm
500 = +09
1000 = +13
1500 = +17
2000 = +21
2500+ = +25

So for cranking it only reads the idle map?

Spooledup300z

no for cranking it reads the cranking/start map, The cranking maps get there signals from the coolant sensor..

easy p-cheesy

Ok I tried to start it today and it ran for a little bit, then killed itself off. I've attached a screenshot of the log. Are the injectors supposed to be at full bore like that?

Infini IV

Wow, definitely not!

Here is a datalog of mine from a short 2nd gear sprint, then I let off. Injector open times drop to 2.1x, then stabilize at idle at 2.33mS:

easy p-cheesy

a few things I'm noticing:

I'm getting constant Load of -02HG

I keep getting an RPM error that's coming on, but I thought I had that fixed.

Is there any other info that might help out?

The injectors are stock S5 550s for primaries, 720ccs secondaries.

easy p-cheesy

For the lazy ones that don't want to read full sentences and paragraphs, see abridged version at the bottom.

Good news, bad news.

The bad news is I am not going to say "This is what the problem was the whole time." and it's fixed now, because it isn't.

The good news is I have some more information that's kind of making things piece together a bit better.

I had a bit of time yesterday to work on it, and I figured some more things out.

I double checked the map line to see if the MAP was actually reading pressure or anything like that. Sucking on it got it to ~14Hg and blowing about 2PSI, so it's reading. I then moved it to the side nipple on the LIM (under BAC) and it was reading some pressure changes.

That got me thinking. If that nipple on the UIM wasn't reading pressure changes, could the others on the UIM not be reading them too? The only other ones going to the UIM is the brake booster line, which I don't think there would be a problem with, but also the FPR and the vent lines. I'll hook the map line up to the FPR vac line and see if it's reading anything from there just to test.

The RPM error only seems to come on when the car was running and then dies, so maybe it's just that the ECU is trying to run the car and while still in the ON position sees the RPMs go to zero. Does anyone else know if the MT does this, or am I still having some kind of problem with my CAS?

I was talking to someone about the injectors going at full bore and he brought up an interesting point. He said maybe it was a grounding issue. That got me thinking, pretty much all of the things grounded through the microtech have been acting kind of screwy. CAS is going crazy sometimes, and one of the grounds goes through the MT. Injectors are doing the same thing. When the wiring was redone, I thought it I put it in a good place, but It's definately worth looking into.

As far as what I'm thinking, can someone confirm if my theory about the injectors here is right? Since injectors are ground side controlled through the MT, the MT having grounding issues could be a problem. More resistance being applied by the MT would cause the need for more voltage to be used, right? and then even more would be needed to cross the resistance from the ground wire to the chassis, right? So that'd basically be kicking up the injectors. I was talking to the guy who was helping me on the car last night and he said that before we redid some of the wiring, the ground wire was directly on the battery. Where did you guys ground the MT?
--------------------------------------------------------
Abridged version of findings:
-RPM error only comes on when car is running and dies.
-MAP sensor was not reading pressure on bottom front UIM nipple.
-MAP sensor was reading pressure with me blowing and sucking on it.
-MAP sensor was reading pressure from side LIM nipple.
-Battery chargers/jumpers are very good inventions.

Abridged version of questions/theories:
1) Could it be a grounding issue? (specifically the MT's grounding).
2) Bad MT ground could be increasing the injector control wire's reistance and raising output. Is this correct?
3) What would cause the MT to not read vacuum from the bottom front UIM nipple?
4) If the front bottom UIM nipple isn't giving pressure signal, what about the rear nipples, could they be having trouble too? Could the FPR be getting no signal?

OK, I think that's it.

easy p-cheesy

I just remembered the reason that I thought of earlier that I forgot but just now remembered for why the MAP sensor wouldn't have been reading from the front UIM nipple. It was running through the arc in the UIM by the fuel rail and could have been kinked or something.

easy p-cheesy

Update time:

When I was working on it today, I went to test the front lower nipple to see if I could blow air through it with a vac line and I couldn't. Same with the middle and top ones on the front, as well as the two on the back that I tested. I could blow through the one on the LIM, but none that I tried on the UIM. What would be the cause of this? I can't think of a single thing that would cause a lack of flow through those nipples.

Since I didn't have time to dig into the UIM to figure it out, I decided to test to see if it was a grounding issue. I measured the resistance from the place the MT was grounded to the (-) battery terminal and I got 7.9 ohms... I didn't have my thicker wire with me for some reason, and I didn't have my solder so I could solder it all up and finalize the wiring, so I did what anyone would do. I took two 14g wires, doubled them up, and crimped ring connectors on each of the ends and ran it from the place I grounded the MT to the (-) battery terminal. Hooray for ghetto! It's only until I can solder things up nice and good (I'm thinking I'll make myself a super 1337 HKS style grounding system while I'm at it).

After unflooding it from last time I tried to start it, It started up and ran. Not too well, but I think that might be because none of the vac lines on the UIM are getting any pressure changes and lots of oil in the engine from previously trying to unflood it. Also I think the spark plugs aren't as clean as they should be. But first on the list is figure out what is wrong with the UIM.

Here are two logs. The second one is the initial startup, the first is after I stopped playing with the throttle so much.

easy p-cheesy

I was just talking with someone about the whole UIM problem I'm having and he reminded me about the UIM to TB spacer. I probably have that in backwards... Hopefully that's it, but if it is, I'll feel kind of dumb.

RETed

Yep, out of the 3 on the front of the UIM, only the middle one sees vacuum and boost.
The other two only see boost - they are useless for vacuum readings.

If NONE of the three work, the TB black plastic spacer might be flipped backwards.


-Ted

easy p-cheesy

Yeah, I'm pretty sure the spacer is in backwards. None of the fronts are allowing flow through them as well as the ones on the back that I tried.

About the middle nipple being the only that sees boost and vacuum, wouldn't I want the MAP sensor to get both? And if so, why has everyone been telling me to put it on the bottom of the three?

Infini IV

Ted, I'm not sure what manifolds you have (American or Japanese, or if it even differs), but I've had a Southern California USDM S5 UIM, and the only nipple on the front (facing the alternator) which saw both vacuum and boost was the lowest of the three. I've also seen a JDM S4 UIM, and the only nipple on the front which saw both vacuum and boost was the lowest of the three.

RETed

Wait, I got that backwards!
The middle one is boost only.
The top and bottom show vacuum and boost - sorry about that!
Um, my 1987 UIM is like that.
A customers 1990 UIM is like that.
Both are US-spec original engines.
I did a Euro-spec 1990, and it was like that too.
I did a Euro-spec 1988, and it was like that too.
I normally run one fitting to MAP sensor and the other to the BOV.
The rear fitting, I use for FPR.


-Ted

RETed

Wait, I got that backwards.
Sorry for the confusion!
Yeah, the top and bottom fittings will show boost and vacuum.
Sorry to have not been that explicit.


-Ted

Infini IV

Wow, good to know! And here I was thinking I'd have to place a "T" in that vacuum line to get a clear vacuum and pressure signal to the ecu and the fpr.