ACIS and a vaccumm leak?

[Chris R]

I'm not sure if my distributor is fubar'd or not. When I hook the mutlimeter up to it, I get almost no reading. I changed the batteries, made sure it is zeroed, but got almost nothing when I tried to read for 10 ohms and 1k ohms.

I hooked the multi-meter up to the temp sensor, and it read about 1k ohms, though when I just let it set there the mutli-meter deflected after a minute or so. It's about 74 degrees outside (I'm guessing that'd be the temperature of the sensor at the moment.)

Has that happened to anyone? I might need to source another mutli-meter here. This one is pretty old.

 

[Chris R]

Good update here. Digital mutli-meters for the win.

Alright, the old multi-meter was bad. The new digital one from Lowes said that it checked out on all connections. Good.


Next up was the coil pack. I couldn't get the connector off, so I had to punch through the wires (I know, I know :3d_frown. The resistance jumped from .2 to .3, which is in range, but it also spiked to .4, which is not in range. I wasn't sure if that was just a bad connection because I had to jump the wires, or the coil is going out.

I went back and adjusted the TPS with the new meter. Haven't checked out the CSI again, or the water temp sensor, but those are next. I should also be able to check the VF signal much easier now.

The check engine line didn't pop up when I took it out for a drive, so that's a good thing. Initially, I had forgotten to plug the TPS in :nono:, but when I plugged it back in the idle dropped from 1200 down to 700 and got a little bit rougher. The acceleration characteristics changed, but I got a better picture of what it's doing. Under 2900, it misfires, and lags, but isn't terrible. Between 2900 and 3400 it sputters, and runs like utter shit. Hit 3500 and all is cured, the car runs jumps (literally) to life and pulls fine. Sometimes these numbers vary by a couple hundred rpms.

The local mechanic never got with us, so I'm going to have to check and see if the local o riley's or autzones rent out fuel pressure and vacuum kits for reading the corresponding pressures. If not, it'll take me a bit longer as I'll just have to cough up the money for the kits, and money is in rather short supply right now.

So what do you guys think? My problem does sound similar to what the MR2 owner in A-model's post described. But mostly the part about how the car will get worse as it warms up, and how the motor clears up in the high rpms.

According to the TSRM, the igniter is the last thing on the list to replace in the ignition department (coil comes first, we've already replaced the ECU). It really doesn't give any way to check the resistance, so I'm kind of stuck for now until I know for sure the coil pack and distributor check out 100 percent. And ... I still haven't went out and checked each ground either, though I have the TSRM page on it bookmarked. There's only so much time in a day, and there's quite a bit of things on this car to check to solve a misfire, heh.

I'm not really sure it could be a fuel pump issue, except for the relay. I would think that if it was the pump itself, or a clogged filter, or dirty injectors, the motor would not liven up at the top end once it hits the powerband. It would be a crappy run all the way through. I am thinking the relay may be suspect though, because if it isn't switching from low to high properly then that could cause problems at the low end.

A headgasket, well, again, I don't know for sure. I'm thinking that if it was a crack, then it would only get worse as the motor cooled because the gasket expands as it heats up, possibly sealing the crack. But headgaskets are a complicated issue that I don't fully understand.

 

[jetjock]

All you have to do to eliminate the relay is drive the car with B and FP in the diag block jumpered. That'll bypass it. A bad relay will also show up as a dip in fuel pressure during a snap throttle test. I doubt that's your problem but I have seen them go bad. On a turbo it shows up at about 3 psi of boost. On an NA I don't know.

 

[Chris R]

All you have to do to eliminate the relay is drive the car with B and FP in the diag block jumpered. That'll bypass it. A bad relay will also show up as a dip in fuel pressure during a snap throttle test. I doubt that's your problem but I have seen them go bad. On a turbo it shows up at about 3 psi of boost. On an NA I don't know.

The kid who owned it before hand installed a switch next to the cruise control in the dash that bypassed or 'primed' (that's what I remember him saying) it. When switched on it makes the same buzzing sound out of the relay that jumping B and FP does. The switch isn't a toggle (it doesn't say in the 'on' position), and he said he only used it at start up.

If I could guess, I would say that bypassing the relay just throws the pump into "high," so that the engine has more than enough fuel for whatever rpm it's at. But I really don't think I'm understanding the entire concept behind the relay.

 

[jetjock]

The relay shunts a resistor that's inline with the pump. The circuit is fail safe in that this happens when the relay turns off, not on. Put another way the ECU normally keeps the relay turned on, only turning it off for high pump speed during cranking and when the engine needs more fuel at higher load.

Unplugging and jumpering the resistor is another way to bypass it but the method still leaves the relay in the circuit. The relay shouldn't buzz when jumpering +B and FP. I hope it's not buzzing with the engine running. If it does you need to fix it before doing anything else.

It *will* buzz with the key off if another +12 volt source is used instead of +B to power it. Sounds like that's what the PO did. Again, you really ought to fix these kinds of things first but for now just jump the resistor at it's connector to run the pump at high speed. You can bypass the relay by unplugging and shorting the two big contacts in it's connector together. If things improve you can go from there.

 

[Chris R]

The relay shunts a resistor that's inline with the pump. The circuit is fail safe in that this happens when the relay turns off, not on. Put another way the ECU normally keeps the relay turned on, only turning it off for high pump speed during cranking and when the engine needs more fuel at higher load.

Gotcha. I think I understand it now.

Unplugging and jumpering the resistor is another way to bypass it but the method still leaves the relay in the circuit. The relay shouldn't buzz when jumpering +B and FP. I hope it's not buzzing with the engine running. If it does you need to fix it before doing anything else.

That's something I'll check for today.

It *will* buzz with the key off if another +12 volt source is used instead of +B to power it. Sounds like that's what the PO did. Again, you really ought to fix these kinds of things first but for now just jump the resistor at it's connector to run the pump at high speed. You can bypass the relay by unplugging and shorting the two big contacts in it's connector together. If things improve you can go from there.

The key has to be on for the switch to do it's job. So the switch would turn off the relay, which turns off the resistor, thus allowing the pump to go into high output mode, which gives the motor more fuel at startup and high load.

A relay isn't that expensive (11 something from rockauto parts) and I don't want to go around with a paper clip in my diag box, or alligator clips on my fuel pump connector, heh. So I'm not thinking of this as a 'fix,' just as a way to see if this is my problem.

 

[CRE]

Disconnect the Round yellow connector with 4 wires running to it from the resistor/relay. Jumper the Blue w/ black stripe wire and the Black w/ red stripe wire. This will bypass both resistor and relay.

Didn't we already do this?

 

[Chris R]

Disconnect the Round yellow connector with 4 wires running to it from the resistor/relay. Jumper the Blue w/ black stripe wire and the Black w/ red stripe wire. This will bypass both resistor and relay.

Didn't we already do this?

I think I got focused on something else, but I went and did it today. I jumped the B+ and FP connections, as shown here in Shaeff's diagram.

I think that's what jetjock was talking about. Today was the first day I went out and drove the car with it jumpered. The engine smoothed out quite a bit. It seemed like it regained a lot of power, and the transition from the low end to the high was smoother. I didn't notice any of the bogging, even between 2900 an 3400 RPMs.

But today I only drove it about 30 miles. On Friday I've got some stuff to do for work, and a haircut to get so I'll be doing about 70 miles of driving. Yeah, Dorthy and Toto would be proud of how remote this town seems, especially if they have stock in gas companies. But anyways, I don't think I'll be entirely convinced that the bogging problem is solved until after I see how it acts Friday.

It's still throwing a code during driving, so later tonight I'm going to go check that out.

Also, the idle is still a little bit rough. What it does is that if I let it idle for a bit, the rpms will just go slowly decrease and the hunting will get worse as it goes down. It usually idles about 900, but once it gets down to about 650 it is like it's hunting or a 'sucking' idle.

The engine still lopes and shudders (loab, lope, eh, same difference in my engrish) after I warm it up and let it set.

But, on the plus side, before, after it started loping the engine would run like utter crap for about 10 miles. Now it seems to pick right up as soon as I drive off.

So I still have to figure out what is throwing that code and what is causing the rough idle, but the car, at least for now, seems to drive a lot smoother. So I'm going to go ahead and order a relay and coil pack (just in case, the resistance didn't check out just right) tonight and see what that does.

 

[CRE]

I think I got focused on something else, but I went and did it today. I jumped the B+ and FP connections, as shown here in Shaeff's diagram.

Yeah, that's what I was referring to as well. I was thinking that at the Diagnostic box FP might not bypass the resistor and relay, but it does, so either location would have been fine.

 

[Chris R]

Yeah, that's what I was referring to as well. I was thinking that at the Diagnostic box FP might not bypass the resistor and relay, but it does, so either location would have been fine.

Well, I noticed that when I jumped the connections at the diag box, the relay buzzed. Same as when I used the switch.

But when I jumpered the connection at the relay box connection, the relay made no sound. But there was an obvious difference in driving. I haven't test driven it with the diag box jumpered. I just used a paperclip on both, since this was only for a test and not a permanent fix.

 

[CRE]

It may be worth testing to see how much power is making it to the relay from the battery.

 

[Chris R]

It may be worth testing to see how much power is making it to the relay from the battery.

Good idea, I'll check that out. Just to be sure, should I be worried that no noise was made when I jumped B+ and FP at the connection? I wouldn't think so, since it seemed like the point was to bypass the entire assembly altogether.

 

[CRE]

No, if you had the relay disconnected it stands to reason it wouldn't make any noise.

Oh, and have you checked to see where the hell that switch is wired?


EDIT: Actually, the lack of noise at that point helped reassure us as to the source of the buzzing.

 

[Chris R]

No, if you had the relay disconnected it stands to reason it wouldn't make any noise.

Haha, common sense told me that, but sometimes it's better just to ask. Especially when it comes to electrical.

Oh, and have you checked to see where the hell that switch is wired?

I've tried poking around under the dash, and checking on the other side of the firewall, but I honestly couldn't find the two wires he used, which were red and yellow (didn't notice if they had stripes on them or not).

There's nothing strange or out of place that I can see running to either the relay or the diag box, so I'm guessing he split into the wires further back in the engine. Probably just to keep the bay clean.

EDIT: Actually, the lack of noise at that point helped reassure us as to the source of the buzzing.

If the car did start randomly buzzing at me, or self destructed for that matter, I can't say I'd be all that surprised.

 

[CRE]

Haha, common sense told me that, but sometimes it's better just to ask. Especially when it comes to electrical.

It's ok... nothing wrong with trying to be sure.

I've tried poking around under the dash, and checking on the other side of the firewall, but I honestly couldn't find the two wires he used, which were red and yellow (didn't notice if they had stripes on them or not).

There's nothing strange or out of place that I can see running to either the relay or the diag box, so I'm guessing he split into the wires further back in the engine. Probably just to keep the bay clean.

Haven't tried using a multimeter to track it? How precisely does this switch effect things?

Never guess about someone else's custom wiring... it'll bite you in the ass.

If the car did start randomly buzzing at me, or self destructed for that matter, I can't say I'd be all that surprised.

Neither would I.

 

[Chris R]

Haven't tried using a multimeter to track it? How precisely does this switch effect things?

I honestly wouldn't know how to track it with a mutlimeter. The switch makes the relay buzz, and it helped the car to start up a bit easier on a cold start. I ever flipped it on while I was driving the car, so I can't say what happened there. The switch burned out not too long ago though, though I really can't see that as the cause since the switch was only used at start up and that's it. As I said, it wasn't an "on and off" switch that stayed in the on position. It just reverted back to the off position as soon as you let go of it.

Never guess about someone else's custom wiring... it'll bite you in the ass.

Good point.

 

[CRE]

Well, does the switch need to be in one position or another to start the car?

One side of the switch is going to supply either 12v or a ground. I'd try that first, then knowing which you'll know the next place to check. If it turns the pump on without the key in the ignition then it's supplying 12v somewhere after the relay.

Have you checked to see what error code is stored or did I miss it?

 

[Chris R]

Well, does the switch need to be in one position or another to start the car?

To start the car at all? Nah. The car starts (or tries too anyways) regardless of what position the switch is in. You see, I'm not entirely sure of the reason why the PO put the switch on. I asked him before I bought it, and he mentioned something about priming the pump, but the specific reason escapes me. I'm thinking it was to help give the fuel pump a "boost" on a cold start, or something along those lines.

One side of the switch is going to supply either 12v or a ground. I'd try that first, then knowing which you'll know the next place to check. If it turns the pump on without the key in the ignition then it's supplying 12v somewhere after the relay.

The key has to be in the ignition, if I recall. And it has to be in the on position. I'm pretty sure on this, but I haven't used it in awhile.

Have you checked to see what error code is stored or did I miss it?

I had cleared the codes, but then went and drove without the TPS plugged in, on accident . So that might of thrown a code, but no check engine light showed up while I was driving, or after I plugged the TPS back in and restarted the car.

Today it threw a code on the highway, like it usually does after about 15 minutes of straight driving on the highway. Sometimes the engine light turns off, sometimes not. Guess it depends on the mood of the car at that given time.

Previously it was throwing a 21 (O2 sensor) and a 43 (starter). The starter doesn't seem to be giving me any problems, though sometimes it can be a bit of a pain to start. That could be the CSI though. I need to go out and test the resistance on that when I check for codes tomorrow. I'm not sure if anything else would cause the ECU to throw a code 43 other than a starter going bad. I know the coil belongs to another code, but could problems with that cause the ECU to throw a 43?

As for the code 21, we replaced the O2 sensor and cleared the computer. As I said, it threw a code earlier today on the highway, but I haven't went out and checked what it was yet. It's in my plans for tomorrow. I think it'll be interesting to see if it keeps throwing a 21, or picked something else up. I'm kind of thinking it'll be another 21, but we''ll see.

 

[CRE]

You can get a code 43 from just pop/push starting the car. I don't remember the implications of this happening, perhaps JJ will remind me? (HINT )

It's been said that a bad O2 sensor would effect your mileage but nothing else... Although, I'm not so sure that would be the case. What if it's just skewed enough that the ECU thinks it needs to add a lot more fuel or pull more than is really called for?

I'd fix the o2 sensor, test the STA pin at the ECU for 12v when the engine is being cranked and find out what code is being stored... all obvious stuff.

 

[Chris R]

You can get a code 43 from just pop/push starting the car. I don't remember the implications of this happening, perhaps JJ will remind me? (HINT )

If I did, which I may have, it's because I was on a hill with nothing better to do. Boredom gets to people sometimes, heh.

It's been said that a bad O2 sensor would effect your mileage but nothing else... Although, I'm not so sure that would be the case. What if it's just skewed enough that the ECU thinks it needs to add a lot more fuel or pull more than is really called for?

Right. I've read that something else in the air flow management system can push the car into thinking that it's the O2 sensor at fault. This could be from something causing the car to run rich, or maybe even lean. Though, I smell quite a bit of fuel. So either it's coolant 3d_frown or the car just runs ridiculously rich at some points. I'm thinking it's just running rich, but I don't want to just take a wild guess and blow a hole through my pistons.

I'd fix the o2 sensor, test the STA pin at the ECU for 12v when the engine is being cranked and find out what code is being stored... all obvious stuff.

Sounds good. I'll check it out and get back to you.

Btw man, you must have a late night job, or get just as bored between semesters as I do.