running rich after replacing head gaskets, i replaced the map sensor, coolant temp sensor next to the thermostat and a couple other things i cant temember. i have removed the ac completely and and smog pump and everything that side of the water pump. i am about to take the thing to a speed shop and have them make a new map for the thing.
i have not read the codes becuause i am out of the area. ill get a cable and download aldata when i get back.

 

Perhaps your o2 sensor has been contaminated with antifreeze or silicone? Either one will render it useless.

 

yeah, o2 sensor is one of the things i forgot i replaced. the shop i was going to take it to (national speed in wilmington NC) wants like $450 for ecu tuning. i cant think of anything else that would be doing this.
the last thing i can think of ding before i started getting this bad, was running some z max through the oil and fuel. maybe it burned up something in the fuel system?

 

Make sure the map sensor is hooked to manifold vacuum, use a tee & gauge to check it.
Check the timing & make sure it advances when you rev it, follow the directions on the emissions label.
Check the ecm grounds & the coolant temp sensor resistance (it changes at different temps).

 

have you checked to make sure all the grounds are completely hooked up. they are on the back of each head.

 

ex-x-fire:
i made sure i hooked up the new map sensor exactly the way the old one was but didnt have the gauge to check it, so that is on the list.

i did the timing but i dont think it was changing as i reved it, even after i reconnected the tan and black wire. what could be causing this?

i have never messed with the ecu, so checking the grounds there will go on the list, i will have to go get a meter to check the resistance on the CTS so thats on the list too.

one92rs:
i made sure i hooked up all the grounds when i put the heads back on. i dont think there is anyway to screw that up, but ill put it on the list as well.

thanks guys this is helping a lot, any idea why the timing would not be advancing when i reved it,? even after the reconnected the wire?

(to adj the timing disconnected the tan and black wire by the firewall on the passenger side. i hooked up the light to the #1 plug wire, marked the slot in the balancer, and rotated the distributor until it was at 4* it didnt advance when reved with or without the wire attatched.) and ideas?

 

Pull codes...first clue to ECM based fault is the one blink CEL at key-on not happening.
Memcal failure?

 

i will plug in the laptop as soon as i get back. yes the SES light is always blinking.
what is a memcal failure?

thanks guys

 

so when i plug in my computer with win aldl, will it be able to tell me there is a fault with a ground to the head, vs map sensor, or ecm etc?

 

If it's always blinking then you have an ECM/memcal failure and it's running in limp home mode. That has to be fixed before you move on to your post below.

I'm not sure what Winaldl would do if your light is blinking? Check engine light should come on, then blink once and stay on when key is turned on, before start.

 

well i dont think it has been in limp home mode. the power feels the same as always and i had no shortage of power drifting it with all of the above going on.
other than that it sounds like i have a path to follow to fix this. thanks guys, ill let you know how it plays out when i get back

 

If you had enough power to drift, you were not in limp home. But if your CEL is blinking with engine running that means some complete failure of ECM or MEMCAL. So I don't know? I'm confused?

 

who knows man, the car also has a rear end from like a 86 in it. bunch of wierd stuff in this one.

 

ok, update time:
i checked the egr and its good

i dont have a T gauge to check the vaccume to the map sensor but when i unplugged the vaccum line from the map sensor the the back of the TBI (at the map sensor) the car died. plugged it back in and restarted no problem

the timing does advance when i rev the motor. i have it set at 4* for 87 octane. when i reved it, it advanced to 8*. on wierd side of theings; the tan wire with the black stripe that you are supposed to unplug when setting the timing does absolutely nothing. i unplugged it to set the timing. reved it and the timing advanced. i hooked the wire back up, still read a steady 4*. i reved it again and it went to 8* again exactly as before. WTF. i have no idea what this means.

i checked the resistance at the coolant temperature sensor at 175 degrees and again at 205 and it was different so i'm solid there too. (like 230 and 175 ohms respectively if anyone was curious)

it was dark by the time i got to re-checking the grounds on the back of the heads but from the top, with a flashlight and hand, the looked and felt good. i will try again tomorrow in the daylight and again from below

i have not checked the ecu grounds yet at all.

one thing a friend suggested to me was an exhaust leak. probably at the manifold, even if i cant feel or find it in anyway. so i bought some new exhaust manifold gaskets and red RVT and ill do those again. same for the manifold to Y-pipe connections. one other thing is that i cut off the factory exhaust before the cat, and rigged up a dynomax muffler where the cat was with just a turn down at the end of the muffler (in the middle of the car) could the change in back pressure or something be messing with the computer, and causing it to run rich?

thanks eveyone i appreciate the help and patients with the geographic delay.

 

your ecm is not advancing the timing. when the ecm is running the car it will no where near 4 or 8* when idling. you have a problem with the ecm.

 

also, the ses light flashes while driving, and i never could get WinALDL to talked to the ecm, even after trying every configuration i could. i think both of these support your conclusion, yes?

 

Ignition timing affects the vacuum the engine makes, which throws off the map sensor. Hook up a vacuum gauge to the manifold, should be above 17.5" at idle. You can try cranking up the timing to 18 degrees to see if it'll make anymore vacuum & run leaner, I'd only do this as a test because the car will be hard to start.

 

i have to drive it for five or ten minutes before it goes rich most of the time(warming up?) wouldn't running at 18* cause detonation?
or would it not in this case since the computer is not automatically advancing it?
the bit about the computer not advancing the timing makes perfect sense because the a/f ratio at idles is fine.
thanks

 

Your timing should advance as far as 36* under normal driving, I picked 18* because is in the middle.
You might not notice its running too rich before it warms up, cold engines require much more fuel to run. You might not notice anything at idle because your timing is close to spec.

 

ok cool.
i picked up a new computer today. im in the middle replacing the motor mounts and front suspension. as soon as i get the other motor mount it, i start her up and see whats what. it will probably be a couple days before she is off the jack stands and i can drive her though.

 

ok, no longer running rich. the new ecu/ecm/ecc whatever you want to call it fixed it. however, when it was running rich it was a consistent and smooth ratio. (using air/fuel ratio gauge) now it is all over the place and random. after driving all over town, doing errands for a few hours, she started idling higher and higher (first 900, then later up to 1300) and at erratic air fuel ratios. the gauge is accurate. you can clearly hear and feel it, and the A/F ratio pegs the gauge at rich, then pegs it out at lean and back and fourth randomly.
while driving, sometimes the SES light is on, sometimes its off. does not flash anymore.
on the other note, having the tan and black timing wire plugged in, does advance the timing now. i have it set at static 4, maybe 5 degrees. with the wire plugged in it looked like 12 or 14.

help... please...
i am supposed to go drifting this sunday, may have to post pone to the 18th. i have a lot of parts coming in, but not a lot of time to put them on.

 

up date; i am getting about 17 psi of vacuum at the manifold, hard to tell exactly, the gauge is kind of coarse. also at wide open throttle, the gauge is at the 2nd of 3 lights in the rich range and constant. so at idle its all over, during normal driving its all over, but WOT is still rich and consistent.

 

i drove 5 hours to charlotte and drifted for about 7 hours pretty much straight. just stopping to change tires. motor ran like a raped ape. still rich at WOT, still all over at idler and idle still does what ever it wants rps wise (from 500 to 1500 but steady) and A/F ratio constantly fluctuating. as long as she kicks *** on the track and gets me home i guess i dont care. i also got between 25-27 mile per gallon on the highway getting there.

 

it should show a little rich and constant at WOT, this is because it is NOT reading the O2 sensor at WOT. it is basing fuel requirements on ecm programming only with no feedback.
if you have stuff you need to check or other issues, im local to where you are, and i have lots of spare parts.

 

i had the coolant flushed, codes checked and cleared. it showed 22 and 42. tps and est. i had a duralast (autozone) tps from last year, so i got that replaced for free. i was running 8* advanced spark timing with premium fuel, and bumped it to 10* because it was running rich, so i was not surprised that EST showed up as a code. but i cleared them again after that and no codes have shown up since.
i took her to myrtle beach speedway and drifted her at the event there. she held up good other than breaking the welds in the diff again. i cleaned everything up, and with a little help from some friends she was re welded and i was back on track.
a/f is still up to its same old tricks.

atomic, just to be clear, these cars intentionally ignore the o2 sensor at wot? they are designed that way?
thanks for the offer man, i may well hit you up. i am out of town a lot this year though. you dont have a 4th gen disc rear do you?

thanks

 

i have a question, im new here so hello every1. im having an issue with my 88 formula tbi, bone stock 102k miles...it smells very rich from the exhaust and im getting code 13 from my trusty paper clip mod lol the car runs smooth idles ok slight 100 to 200 rpm surge here and there but nothing terrible, changed all the filters and charged up the a/c, i sprayed starter fluid around the intake and the rpms go crazy bogs almost dies so i have some work to do there maybe vacuum lines i hope, i was trying to set my timing until i seen this W shaped pointer with a round tube next to it?????? wheres 0 degrees on this setup also at idle its about 3.5 inches to the left of the pointer there are no numbers that i can see on the damper so i assume its retarded. ineed to get this fixed i just took it ti emissions inspection and the hc ppm was 1023 normal is 220 and my co% is 9.88 normal is 1.20 any advice will be great thankyou!

 

You gotta track down those vacuum leaks and fix them before you can do anything else.

 

ok i took your advice i replaced the entire vacuum line system(30ft of it!). it does run alot smoother at idle i didnt get a chance to road test it, ill do it in the morning i unhooked the battery cables to reset the system ill leave it overnite and hopefull code 13 will stay home , so after that ill check the timing and tps with the ohm meter tomorrow..on a good note the exhaust seems a little weaker smelling after the vacuum redo...

 

Now drive the car around for awhile and see how it reacts and what not. If any problems persist than you can continue diagnosing the problem.

 

yep, it switches to open loop at w.o.t. all gm injected vehicles do this, until sometime after they went obd2. cant say exactly when but i know the 95 lt1 cars are still the same. it has to do with the limited accuracy and speed of the o2 sensor.
no disc rears, the only one i have is drum, 3.23, open, 1997 firebird. (65 inches wms to wms)

 

well the vacuum seems to be ok...i put the ohm meter on the tps and it reads a steady .07 with no increase at wot so ill be changing that today.

 

ok i need some advice here i removed the tps sensor and its functioning smoothly But when i measure it from the plug that connects to the tps while its hooked up i get .57 with no increase at wot also no check engine light but a slight surge in rpms

 

When you install the TPS make sure the tab is on the correct side of throttle linkage so when throttle opens it moves. Wrong side throttle opens and it does not move.

 

i will tripple check that...brb

 

its set properly ...bot aaaaahhhh haaaaaa the connector that goes into it has broken round black tabs and the clip is broken off so it seems sombody was here before. autozone has it for 12.99 so ill put it in when it cools off outside later on, hopefully its just not making a connection...

 

ok good news and bad news i replaced the pigtail to the tps sensor, found a ground its putting out .56 ohms at closed but when i depress the gas pedal (slowly) it jumps all over the ohm meter up to 6.88+ and wot then voltage drops to .48 without letting up on the pedal do you guys and ladies think its a faulty tps at this point i dont have any codes or lights on the dash btw, i just dont wanna spend bucks that i could use on somthing else that she could need...thankyou again you 3rd gen guys are alot of help so glad i sold my mustang the tbi may not be as quick but the hood and headlights just look cool at night from behind the wheel and she will out corner and out stop the 5.0 all day!!!

 

It should be like .54 volts not ohms if i remember correctly at idle.

 

sorry bad habit with the volts...i set the ohm meter on dc 20k and it wont go lower than 0.67 and 4.40 @ wot by using small amount of play in the tps and the hex screw on the tbi unit i also set the timing @ 2 degrees advanced which i believe is going from left to right in the inside of the second groove (wv) looking pointer it was about 3 inches to the left of the pointer all together before hand i tried to set it @ 0 degrees again assuming its the inside of the large wv groove is 0 degrees but it wasnt happy there no power bad hesitation ...new to the gm tech world so please excuse my repetitive questions but just trying to get a handle on the correct specs so i can get her through emissions here in nj.

 

If I can remember off hand I believe the base timing should be 6 degrees btdc with the est connector unplugged. Thats stock setting anyways. If your actually throttle and tps sensor are off from one another it could cause a hesitation also. So I would set the timing to stock then set the idle to stock specs and then adjust the tps to match. Just to make sure everything in the chain there is correct

 

stock timing on a tbi engine with the connector unplugged is ZERO degrees.

 

ok heres my update as of today...changed all filters and 30+ feet of vacuum hoses..hard plastic lines are discontinued from gm so went the autozone route...set tps to .58 set timing to 0 degrees cleaned everything with carb cleaner and a toothbrush and went to our beautiful Nj inspection station. so last time before i did anything the readout said Idle fail = hc ppm 1023 should be 220..co% was 9.88 should be 1.20, the high idle was 918 should be 220 and the co% was 11.46 should be 1.2 ....so my after math results are, Idle fail hc ppm 335 not 220 arrrrgh, co% is .64 way under the 1.20 standard, the high idle was hc ppm 69 instead of 220 double arrrgh and the co% was 0.12 standard is 1.20 so all i failed for was the idle being 115 points higher i even retarded the timing a few degrees and went back through to only see a 4 point drop in the idle hc ppms. i need some advice here im so close but yet so far.

 

Well you are a step in the right direction. They do not tailpipe test cars here in Mass so I have no experience with the measurements and what causes high readings so you will have to wait for somebody else to reply.

 

thankyou, i think im out of steps lol the next one is the fall.. i must have missed somthing somewhere i just got back from a cruise in her i was thinking possible AIC or EGR but i removed the iac and cleaned it and the hole it goes in...the egr looks like it was replaced at some point cuz its shiny lol maybe the previous owner put a lower t-stat in it and i should try a 195 to try and heat it up a bit ...i havent pulled the plugs yet, im getting no codes its putting out less emissions than a prius at 2500 rpms lol too bad they dont grade it on a curve

 

update...didnt change the plugs or wires or any of that. i set the timing back to factory 0 degrees, reset tps 57-58 put 1/2 tank of regular 87 gas + 3 large bottles of 70% rubbing alcohol...and BAM! good till 7-2013 baby. reminder i did change alot of parts ,the entire vacuum line system and all filters, cleaned the tbi and iac unit, new tps plug mine was shot, but after all that i was still off on the emissions by a hundred point on the smog...3 bottles of the alcohol was the answer hope my thread can help!