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New Injectors on TLAO Surging Idle?

Is it possible I'm dealing with a speed sensor issue?

Anyone know how to test such things? I would assume that my speedo would stop working but... it SEEMS like it works fine.
This thread made me think about it.
https://forums.tbforums.com/showthread.php?t=275547

The only other wild card I can think of is that my coolant gauge hasn't ever worked. The other day in traffic (stop and go) and temps in the 80s with my car revving itself constantly it started smelling pretty hot. As I had just pulled my old motor (lh 2.2 (87 244)) I grabbed the coolant gauge sensor (not the ECT sensor) from that motor and popped it into my 93 245 as I thought they were compatible? Maybe I yutzed something here?
 
Current symptoms are erratic idle.
Starts up every time no issue.
Stalls on pressing clutch in during decel sometimes. Other times it'll catch itself.
Sometimes it will idle dead perfect ~800 and other times it will idle at between 1500 and 2000 hang there for 3 or 4 seconds and then drop down to 500 before bouncing right back up. This is opposed to what it was doing before where it would just vac leak idle constantly back and forth from ~1k to ~2k+ with no change in rhythm.

Car drives fine. Popped a couple of fireballs yesterday on the way to the grocery store (I have side exit...)

I'm getting no CELs and no codes. IACV is cleaned and lubed (also swapped to a new Bosch unit for testing. Same results) I've tested all the usual culprits sensor wise and everything has come up clean. I've looked and looked and looked for vac leaks. I haven't come up with any (though ORIGINALLY when I made this thread the IACV hose was cracked on the IM side. This didn't show in my smoke OR boost leak tests for some reason...)
 
Have you checked and cleaned the MAF? It was a known working good one right? When I had a bad MAF on my car, It wouldn't idle, and as soon as I unplugged it the car would idle right away, but any throttle input and it would fall on its face.

The idle function in LH24 is super basic, and there is only a couple things that can really muck with it.

Betcha its a bad maf, unplug it, and fire up the car and report back.
 
So the amm is known good in so much as I plugged it in on my old tune with the new injectors and everything seemed fine. This test is what prompted me to do the battery/ECU reset and then my issues went crazy.

It's not showing any amm codes... Or any for that matter. If I unplug it while the car is running, it dies.

I was unsure of how to test the 012 amm though so I haven't checked it's resistances or anything other than what I posted here.

Thoughts? My understanding was if I unplugged it while running and the car didn't straighten out, it's not the amm.
 
What about putting my stock amm back in? I'm under the assumption that the stock amm isn't able to handle idle with 577cc/min injectors?
 
EivlEvo said:
So the amm is known good in so much as I plugged it in on my old tune with the new injectors and everything seemed fine. This test is what prompted me to do the battery/ECU reset and then my issues went crazy.

It's not showing any amm codes... Or any for that matter. If I unplug it while the car is running, it dies.

I was unsure of how to test the 012 amm though so I haven't checked it's resistances or anything other than what I posted here.

Thoughts? My understanding was if I unplugged it while running and the car didn't straighten out, it's not the amm.
Click to expand...

The correct AMM for 2.4 should be 016, assuming that is what you had on there, I would go back to the first injectors and a 016 AMM and see if that cures what ails.

The correct response from a functioning AMM when you test (it's a bad test, and the reason why so many people have trouble with LH 2.4 is there isn't really a good way to test the AMM) is for the car to drop idle a bit when unplugged, and die as soon as the throttle is touched.

My car wouldn't idle until I unplugged the MAF, so I knew something wasn't right with it.

So something I have not done a ton of research on, But I am not sure the resistance of your new injector is correct for the ECU. I thought the resistance on an injector was in the 16 ohm range, and your 55lbs are 12.2? Not sure if that could cause an erratic idle, but If they are not closing all the way for some reason, that would make the idle suck, and the car would try to compensate?

Purely conjecture until someone way smarter than I chimes in.
 
Ah... Now THIS IS interesting to me... Because you see I'm pretty dumb and essentially thought high imp was high imp but now... Hmm...
 
Anybody have any info on impedance? I searched but couldn't come up with any numbers for the highs.

The car is definitely learning rn which leads me back to what Sbaabs (iirc) was saying about revving during the learning. I'm only getting some minor revving now, it's seeming like it's trying to hunt to get to the correct idle.

The car does stall quite a bit on clutch in decel. It will usually try and catch itself as it dips into the ~500rpm area, but then seems to close the IACV again and it just dies (or floods... haven't checked)

When I walk the throttle down to near idle RPMs it can usually catch itself, but while it's hitting the proper idle, it's rough and shaky. The car doesn't like it and then brings the idle back up into the 1300 range before trying to walk itself back down. Then it gets into some rev matches.
 
Well kiddos. After wracking my brain to help trying to find this second "vac leak" it is in fact the amm. This is now confirmed as I pulled my 012 and plugged my 016 back in and the car idles just fine (I mean... Rich as all hell but no more of this surging nonsense. So... Need to grab another it seems.
 
I tried it both ways. I'm trying to eliminate variables.

When I replaced the hose on the intake side of the IACV (with the proper Volvo hose DESPITE my rigged thing not leaking... just to have one piece instead of hose clamp hell) I started it up and it did the same thing. Since the car was cool, and nothing had shown up with my smoke OR propane, I went shooting carb spray over the strategic areas. I got nothing with this (though admittedly, it's incredibly challenging when the idle is surging anyway).

So... while it was running, I unplugged the 012 AMM. This caused the madness to stop. I didn't go look at my gauges but I'd guess idle was about 800-1000 and going pig rich. Plugged it back in and same nonsense.

Then, I shut it off. Cleared my codes. Swapped my 016 AMM back in. Started it up and it idled fine. Again... pig rich.

Then, I shut it off and pulled the battery. Swapped the 012 back in. Started it up and after hunting about for a few seconds it went right back into the idle revving. I unplugged it while running, and it settled down. Plugged it back in and revvy revvy.

THEN, I shut it off. Pulled my FILTER because my filter clamp is the size of the 016 and I thought... maybe I'm getting some weird bernoulli crap happening here (this happens lots with Evos MAFs when you mess with the airflow TO the MAF). Essentially ran it open AMM. Same deal.

Short story long. Plugged my 016 back in and it idles crazy rich, but idles without issue.

Officially, I found that my (way back on page 1 or something) IACV IM side hose had a crack in the underside of the upper curve. I actually don't think this "caused" any of this, I think it was ALWAYS the AMM. BUT... vac leaks are obv no good.

I'm not sure why the AMM is bad or how to test it. I got no CELs and the wires seem intact. I haven't tried hitting it with MAF cleaner yet I suppose but... this particular one has no screens on it and I was hesitant to mess with it too much.

Any advice?

I've got another 012 on the way... hopefully here by the weekend.
 
Swapping the AMM back and forth without resetting LH is going to piss it off and give you really bad readings and cause all kinds of issues.

I have seen working AMM's have all kinds of issues, I have had two AMM's that worked and ran perfect, biggest difference was one gave an AFR or 11:1 under load and the other 13:1 under load. All that means is that 20 year old parts with unknown miles in unknown shape can be a pain in the ass to deal with.

If you want you can send me your AMM and I can test on my car and see if it has any of the same issues. Either way I prefer to keep my screens on as not only does it keep large objects from damaging the hotwire it also helps straighten out the air flow for a better reading ( i am told).
 
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I have another 012 en route. I don't disagree that what I'm doing is pissing the car off but bottom line, the ONLY time this amm idled was when I swapped my injectors and this 012 in without resetting the ECU so it was used to dealing with 310ccs and an 016. But even that had me showing 10afrs at idle.

Also this 012 was sold to me sans screens. I hadn't gotten far enough to change them over.

Regardless, I'll check with this new 012 when it arrives and see what happens?

That all said how else should I eliminate these variables? As far as I'm aware swapping the amm provides it exactly the same data stream, it's just showing different values for the same volume of air?
 
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Have you make sure the tps is closed and the sensor clicks when you open the throttle just barely?

For sure no pressure or vac leaks? 02 sensor for LH is new and working?
 
thelostartof said:
Have you make sure the tps is closed and the sensor clicks when you open the throttle just barely?

For sure no pressure or vac leaks? 02 sensor for LH is new and working?
Click to expand...

The TPS indicates within spec via ohms and is adjusted correctly. I've been eyeing this as well and grabbed a new one to test that just arrived so I'm going to go check that. I also have 2 AMMs en route.

I'm 100% not a parts cannon individual but the TPS, while checking out with the ohm meter didn't seem to give the WOT indication in the OBD test.

The OTHER reason I suspected it might be related to that was that the car seems (occasionally) to drive itself when I'm off the throttle... and this seems to be confirmed via AFRs.

The O2 sensor is less than a year old which means nothing I know... and while I can test these with my OBD2 scanner or my scope at the office, I haven't done anything more than observe the voltage sweep via multimeter... which is kind of a meh test.

I've confirmed via BLT and smoke that there are no vac leaks. CONSIDER THOUGH... the original cracked hose that I found didn't show up with propane, smoke or BLT... but that hose has been completely replaced.

I'll report back on this TPS in a bit.
 
Replaced TPS. No noticeable change.

Reset ECU. No noticeable change.

Still leaning towards AMM.
 
The LH 2.4 turbo TPS does NOT have a wot switch. Just an idle and not idle.

If the cracked and leaking iac hose didn't show up on a boost leak test I would question the quality of the test. You should set the system pressure preturbo to 20-30psi and while not only be using soapy water to check for bubbles but also be grabbing and moving everything to simulate the moving of the engine. Also do it on a hot and cold engine. I have found minor leaks that did not cause any issues. Make sure the brake booster check valve is also checked or replaced. Along with cracking open the throttle plate and blocking off the breather hose if you are putting vac/pressure to it.
 
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