Exactly what we are still fighting here with an 85 automatic.
Except the trigger is around 2200.
Am getting a little bit of stumble when I get rolling.
Every once and a while, it launches from the line like a tiger.
Usually not till its up in the RPMs though.
Car ALWAYS starts and idles solid. Its the path from 500 to 2200 rpm that is painful, takes huge throttle movement.

Micro turbo at 2200 or when TPS goes to WOT. Sometimes both.

New coils, caps and rotors last week; correctly gapped new plugs.
All new wires. Various coil wire switches.
New temp II.
Intake job X 2. New rubber.
Same situation, before and after PKchips & 87 FPR.
Three MAFs tried, all work great in the other cars, same performance on this car.
Have tried new O2 sensor and run without (open loop) --- same either way.

I think, in order of increasing probability, its either a harness short, a bad vac-timing adjustment module in brain or partially clogged injector(s). Timing light seems to produce correct results, though.

Have a pair of brains to try this weekend.
Next, I order injectors.

This is about the Van Winkler car. Remember, it sat dead to the world for 10 years. Has new fuel strainer, pump, filter. Could it be varnished injectors????

 

Let me know if you can about the brains. If that fixes it, I am going megasquirt.

I love these cars so much. I feel like I know them (mostly) so well I can feel every nut and bolt, every shiver or wiggle at the limit, and know where and what it means.

But the electronics are just fvcking disastrous, no matter how much we lie about it. I want to just get Ken's chip and be done with it, but if this continues I am ditching the LH and getting MSIII installed. The LH and EZF are on thier own loom, and so installation is not that bad, I have half a loom already for MS, and loom plugs for the coils, etc. Am I the guy that would be stubborn and stay in it and fix this? Of course. But I am getting niggling irritating from a really great car because of this.

Injectors could be it, but I don't see how an injector would cause this other than with fuel pressure changes masking it at certain times. Possible we could rig a vacuum line into a vac gun in the cabin from the FPR and play with that to see if it would be recreated.

Anyone else would drive this car and possibly not even think twice about it. But little **** like this makes me like the princess and the pea.

The hesitation that is bred by this lower power issue showed its hand a bit to me today in that it happened JUST ONCE on a rev run, at 2800rpm, but it was almost as if the engine shut down for a split second. Less that that even.

 

Brendan, if you want a second opinion come by and i'll drive the *** out of it, If I can't hit 110+ between the on ramp at Camino Del Norte and the off ramp at Bernardo Center Drive I'll agree it has a problem, and let you know what I think :-).
Seriously, if you want to, i have time on saturday 26th after lunch, and i'll be happy to go over it with you, if you have a 'bung' in the exhaust I have a Innovate O2 sensor we can plug in and do some readings also.
LMK
Neil

 

I think the injector(s) are partially clogged at the screens and peeing inside the manifolds.
Clears-up, else the loss of the cylinder is less noticeable at high piston speed --- different dynamics.

That's my speculation after all this. Actually, after 6000 miles of incremental improvment, test, tune. Am pretty much down to brains, injectors and/or a hidden short.

 

Hey Neil. Thanks for your offer. The issue is that the car seems to, and feels like it runs perfectly fine above 3k. So if we beat the snot out of it to 110, you may be surprised how fast it is and it still has the problem.

I do have an innovate sensor on loan from a friend in OC. I should probably hook that up properly this weekend and see if the mixture is affected at all by what is happening.

We will speak closer to the 26th.

 

One thing I just realized is that I never tested whether there is an issue in the wires from the Temp II sensor to the computer. I replaced the sensor because its so important, but looked no further.

Have you tested those lines?

 

I am always hesitant to assume its something serious. The difference in my opinion between new and old technology is that in 1986, the smallest issue could cause the biggest problem, and today, the biggest issues sometimes cause no problem at all.

 

Land-

Have you checked the fuel pressure?

 

I vaguely recall you mentioned it has no cats? Duct tape a WBO2 in the tailpipe and go for a drive. See what happens to AFR.

Injectors would be my guess based on what you've tried so far - what rpm point does LH switch the injector pulse to every other rpm? (IIRC, LH2.3 does that.. I'm assuming 2.2 does too). But its a guess. I'd pick up a set of cheap rebuilt 4-hole 24lb drop-in injectors and swap them over, and ebay the old ones.

Questions on the symptoms - can you get to 3k rpms on the cruise map, and does the transition over 3k whilst still on cruise have the same effect?

Or are you only noticing the 3k rpm change in performance when accelerating under WOT?

 

Will meter temp II wires again this weekend. ( son / daughter in law have car this week ).

Only other thing --- I need to check the TPS function and its extension wire. Greg Brown made a passing reference about 6 months ago to a bad-running car at his shop. Turned out to be something wrong with the TPS circuit, but it was on the low side, not on the WOT side of it.

 

I have checked the function of the TPS. It does the release of idle and switching at WOT when its supposed to. I can even tell when I depress the WOT switch because if under 3k, it will make the car slightly lunch forward. Its all PART throttle, and under 3k.

 

Cruise Map. Thats a great question. Does that mean little or no accel?

The change in performance is noticeable mostly at part throttle.

There is almost a tip-in issue with power under 3k and with part throttle. Going FROM cruise to NON-WOT accel UNDER 3k, there is a momentary flat spot, and then a transition to slightly weak power.

 

Land - did your car sit for a while?

 

Yep - cruise map is whats used generally unless the WOT switch is activated, or the load calculation achieves some magic threshold based on MAF input. Even during freeway driving, under light throttle the car should remain in the cruise map.

Can't recall offhand where that threshold is, but as long as the load is under it and the WOT switch isn't active the car remains on the O2 loop. I figure if you're looking for the 3k perormance change while driving, you might be implicitly activating the WOT switch/map to get the rpm increase.


You've already tried changing the O2 sensor - have you tried borrowing an LH2.2 from a local? It could be the O2 control circuit that's rooted. (rooted = aussie slang for f&*cked)

 

Suggest you set up the idle CO as per the WSM.