88 SE

Just got finished putting my rebuild in.. Started it up and its got a few problems.

First off it wont hold an idle. If I give it a little gas.. even at steady pressure the RPMs surge from 1500 - 2000 and so on. Engine also seems to miss a bit through the RPM range.

At WOT it makes a sot of squealing sound. Soon as the engine cools off im gonan look at the plugs to see if its running rich or lean.

I guess I should probably start with my TPS.. What order should I start checking other things in?

SonicRaT

iTrader: (6)

well, the bouncing sounds to be like TPS, or it could be a vacuum leak (those always suck) In that case, bust out the carb cleaner and start spraying like a madman and listen for the engine to rev up or idle smoother while you spray. Have you verified your timing?

hypntyz7

FWIW a fresh rebuild will not hold a normal idle for several hundred miles usually. I usually set mine to 1200 and leave them until at least 1500 miles are done, then I set it down to about 8-900 and leave it. Also a bit of misfiring is common too. THink of it this way, the new engine is a bit low on compression, and low compression equals rough running and unburnt fuel, fouling plugs, etc. IT WILL get better, but dont expect it to be like new the first week unless you used new rotor housings.

Your problems are realated to your TPS it sounds like. However there isnt a lot of use in adjusting this perfectly yet, especially since youre idling up your throttle which will play with the TPS settings too. Wait until all breakin and adjustments have been done to try and make it work perfect.

88 SE

Thats just the thing, i cant even get it to hold any idle. With the screw all the way out it still just sputters and dies.

When I start it when cold it idles at 3000-3200 RPM for about 5 or 6 seconds then just drops down and dies.

ra ra rotory

It sounds like a vacum leek to me. something connected to the throttle body, check it out, its worth a try

J-Rat

iTrader: (2)

As crazy as it sounds, I always start with the ECU codes. Lots of people here say that the S4 ECU is junk, and that may be so, but I have eliminated alot of guesswork, and gotten straight to the problem, just by hooking up the test lights and checking to see whats going wrong.

Rat

88 SE

Actually I want to do that but i havent been able to track down a thread on how to pull the codes.

Anyone care to enlighten me?

88 SE

Well on the plus side it hasnt flooded a single time.

Thank you new fuel injectors!

I got rebuilt units for $28 a piece and wired in resistors at the CPU. seems to work ok

I was surprised, the car only smoked for about 20 seconds then stopped, wierd. oil pressure is great and water temp stays very very low.

Yesterday when i first started the car it idled fine at 2000rpm for a while. When I shut it off and came back later to turn it back on it would no longer idle

I went out and bought a digital multimeter to adjust the TPS somewhat. Can someone tell me how to actually use this thing? :O

When I set it last i used the 2k ohms setting on the multimeter. is that right? stupid thing doesnt have a 1k setting.

hypntyz7

Ah, youre messing with the stupid BAC adjustment. Set the idle with the screw and locknut on the top corner of the throttle body...youll need an 8mm wrench and a little bitty flathead screwdriveer, and youll need to chip away the factory jb weld coating. THis idle adjustment is a true physical adjustment(not a bypass air adjustment which can vary) which holds the throttle plates farther open. THe one on top is more of just a fine tuning deal worth no more than 2 or 300 rpm.

Well the car needs to be warmed up and the throttle set for normal idle or therabouts. Remember that being warm has an effect on throttle position and thus TPS setting. UNplug the TPS connector, set your DMM to kohms(the 2k setting is fine) and probe the green adn black terminals from the backside, while adjusting the large flathead TPS setscrew adn observing the output, you want 1.0kohms or close to that, remember that pushing on teh screw too hard will open the throttle and move your readings way off. WHen you get close snap the throttle open and let it shut to simulate whats gonna happen when you rev it up, and continue adjusting your setting. When you get close, plug it back in. Now its best to go back with the 2 lightbulb method, at the check connector by the afm, and fine tune it perfectly so only one light is on then it is perfect. THe 1kohm is a close ballpark setting, and is actually just a method of checking the overall range of the TPS, but the lights are *the* method to set them and what the ecu reads.

88 SE

BAC adjustment.. no wonder it wasnt doing crap haha

I also made the mistake of doing TPS while engine was cold, could explain the hunting.

Thanks dude, youre a lifesaver

SonicRaT

iTrader: (6)

Well, that explains a lot The thermowax holds the throttle plates open if the car is cold, thus if you adjust the TPS you're adjusting it to the high idle caused by this, which of course isn't correct! (Just figured I'd explain the cause) But anyway, I hope Kevin solved your problem for you!

88 SE

oh ok that explains it. I was about to ask why it would matter if it was cold or hot haha.

You learn something new every day! Or in my case.. 20 things a day.

J-Rat

iTrader: (2)

The ECU codes link

http://home.rmci.net/panther/ecu_codes.htm


Rat