r0taryluv

Hello fellow r0tor headz,

Recently bought a GSL-SE, have had it for about three weeks now and two weeks out of the three I have been working on it more than enjoying the ride. Have tried reading the forums many nights and asking friends on what may be the cause of my problem. Here is the spill..... when I first bought the car I did notice it seemed to be running fairly rich (neal behind the car and burn your eyes rich) needless to say i had a 12a GS and figured this would not be to much of an issue seeings there is an adjustment screw for this problem, but rather than turning ***** and adjust everything I want to be sure there is nothing else causething this. Sorry this might be a long story but want to make it very clear on whats happening and what I have observed. After the first 4 days I decided to replace the radiator seeings the old one had busted the sotter that holds it to its mounts. Well this took a week, do to them ordering the wrong radiator. Now after getting the radiator in and start driving it for a few days, all the sudden one day pulling off in 1st gear the car starts to Buck BADLY(bucking meaning, like when someone is trying to learn how to drive a manual for the first time) the car throws you back and forth and the tachometer bounces in variance of 3k rpms. Now if I ease out on the clutch the car will drive fine, but if you mash the gas "any" then it bucks. After leaving 1st gear going into second, same thing.....now once in 3rd you can punch it and it has no problem going, with very very slight hessitation. I have done the timing, has fairly new Jacob wires,Jacob coils, and brand new NGK plugs,cap and rotor are very clean,k&n air filter,all fairly new vacume hoses throughout,RacingBeat Street Port exhaust system but engine is not ported,smog has been removed and block off plate has been placed.
What I have tried doing so far.
1.) I have tried redoing the timing
2.) Took the spark plugs out cleaned them (they looked pretty black,prolly from running rich) then took the whole distributer out of my 12a which is running fine, put that in the SE
3.) Put vise grips and rag on main gas line under the hood to restrick fuel to see if it was flooding
4.) tried adjusting idle a/f mixture screw to make it idle better.
This is all I have ruled through and am out of ideas to try. The car fires right up does have a slight bit of a rough idle, but once past 1st and 2nd gear your able to dog her. PLEASE PLEASE all help is greetly obliged!!! Would luv to get her back on the road!

BigJim

Throttle positioning sensor. Mine did the same thing. warm up car and adjust it , search if u dont kno how., thats your problem

r0taryluv

Thanx BigJim!!!
I will give that a try first thing tomorrow, think I have some small lights I can rig up here. Will post if that works! Really weird how one thing could possibly trough the whole system off.

Rex4Life

If you don't want to bother with the lights, you can use a volt meter to set the TPS. Search over in the 2nd gen section for "TPS setting" --all the FCs have them and only the 84/85 SEs have them. So you'd have more info available over there. The TPS units are nearly identical for the SE and 86-88 cars.

I just checked mine yesterday and with engine hot and ignition on but not running, backprobe the TPS connector with the DVM. I got 1.05 volts at idle stop and 4.7 volts at full throttle.

The lights method will work just as good but why bother.

My 2 cts.

Scott

web777

Mine did the exact same thing and I thought it was the distributor. I pulled mine out and was going to put in the extra one I thought I had. Turns out I didn't have an extra one. Put the old distr back in the and the problem went away. I have no idea what cause/fixed it.

r0taryluv

Quick question here.... i tested the TPS with a OHM meter and the readings came out 1.77 at idle and .67 full throttle at a setting of 20k resistance. When the reading is supose to be 1kohms at idle and 5k ohms at full throttle. So I am taking that the TPS is bad. This part better to buy OEM or aftermarket fine? Also is a 86-91 TPS the same as ours? Thanx again for all your help guyz! LUV THIS SITE!!!

BigJim

I dont kno, but TPS's are mad expensive. I would say use the 2 light tuning method adn tune it, thats what i did and mine worked fine

r0taryluv

Tuning will not do much good if the sensor is indeed bad. Which I red ........
TESTING FOR A BAD TPS

If you suspect the TPS is malfunctioning (as opposed to being out of adjustment) you can check it with an ohmmeter. This is done with the engine off. Disconnect the connector from the Throttle Sensor itself and orient it like an upside-down face, with the "mouth" on top, and the two parallel "eyes" on the bottom. Connect your ohmmeter to the "eye" on the right and the "mouth" above. Look for a reading of about 1 k-ohm with the throttle closed (idle) and 5 k-ohm with the throttle fully open

The readings I got were no where near what this artice calls for. This is what made me lead to the idea that the sensor has went bad. Where the article called for 1k-ohm i got 1.77 and where it called for 5k-ohm I got .67 so im figuring this means the sensor is burnt out. If anyone knows something else I could try please let me know before I go and buy this $184 part :[ But this would make sense on my problems if this sensor is indeed dead, seeings when I mash the peddle a little more the EFI system doesnt realize that I gave it more gas which in trade off is starving the motor for fuel which makes it BUCK. Any other info. would be helpful....keep the knowledge coming!!! Love learning something new about these wounderful Carz! Im in for the long hall with this SE!

mazda123x5

I think you are on the right track. I tested my tps
when I was learning to set it and I got the correct
ohm reading. Besides my idle not being perfect the car
drives o.k.

r0taryluv

OK...this is getting no where. I have talked to different people and everyone seems to tell me something different. I have been told that the TPS only really deals with the idle tuning not anything that would make the car buck like a 12 year old learning to drive a manual. Someone told me that it sounds like a Atmospheric valve that is somewhere on the passenger fender well. So I guess today I'm going to replace the thermostat that doesnt seem to be opening anymore and replace the fuel filter. Not saying the fuel filter is going to fix my problem but im sure it needs changed and we can all wish it would just be a simple fix. PLEASE if anyone has any suggestions on what to look for or what to try to fix this bucking problem I'm having, please post.

Northern 7

iTrader: (3)

Have you tried setting the TPs rather than jumping to conclusions that it is bad? Why are you testing it?? Set it and see if your problem is fixed. If not, then maybe your TPS is bad but from my understanding, they don't go bad very often

GavinJuice

Sounds like your having the same shitty problems that i am having. Sux don't it?

bizarro

iTrader: (1)

I had that problem way back when...I hooked up the 2 light tester I rigged up and eversince my car's been at a steady 800rpms...

if it is bad then see if you can get a used one from the parts for sale section here or from a junkyard or ebay...like Northern 7 said...these don't go bad often so, getting a used one would be just fine...

LongDuck

This was covered in another thread, but you can't just plug in a TPS and expect it to operate perfectly. It HAS to be adjusted to respond correctly to your 'idle' setting and 'throttle' settings so that the ECU gets a good signal of where the engine is in the RPM range - this, combined with AFM signal, Intake Air temp signal, Coolant Temp signal, and host of other things is what helps the ECU decide how long and how much fuel goes in with the air.

TPS and how it works:

The TPS is a critical part because it tells the engine what you 'want' to happen, compared to what 'is' happening (right now). The TPS at idle does nothing - the engine is in steady-state conditions with A/F driven by Bypass Air Control Valving (BACV) and by idle mixture adjustment (passenger side strut tower). When you apply throttle, the TPS moves out of it's normal 'idle' range, which the ECU determines as being your intention to change something (i.e, engine RPM). This is met with more air coming through the AFM, and decreased Intake Air charge temperature - comes from 2 senders, one in the AFM and one in the Dynamic Effect Intake (DEI) chamber.

The rate at which fuel is signaled to come from the injectors is determined by an electronic chip map in the ECU that compares TPS position against the other factors. Pedal to the floor makes the TPS tell the ECU "Hey, He wants FULL-THROTTLE! Get on it!!" Partial throttle starts result in something less emphatic.

Your problem - lurching and surging resulting in 'bucking' and uncomfortable acceleration. This is due to the TPS sending erratic signals to the ECU about what you 'intend' the car to do. The TPS, if not set correctly, can't tell where you want the engine RPM to be, so the ECU starts guessing from the AFM, Intake Temp, Coolant Temp, etc. - and it guesses WRONG.

Help it guess better by adjusting your TPS, please. Help it to help you... Just a little assistance from you is tall it takes.

Help IT to help YOU.

(sorry, been a weird week)

r0taryluv

OK...updatez.... The values of the TPS were in deed out of tolerence, so after setting it once I did notice a difference in drivability but the bucking was still there in 1st gear... no longer in 2nd...so on the right track. Came back from the test drive and then set the timing,set the TPS again to be sure it was correct,adjusted the main A/F mixture,then took gas cap off unplugged the two selinoids then set the idle A/F mixture. Test drover her again and was SOOO very happy it didnt surge anymore. But yet on the way home from dinner I got on her hard again and same thing BUCKING, but ALOT less harsh(not like a bull but a horse) ;} But something seems off still, when cranking the car it has to turn over a few times before she starts up, not just a turn and start right up anymore. Any new suggestions on what I got going now? Thanx everyone for the advise and the patients.

r0taryluv

OK matters have only gotton worse!!!! I am currently not able to drive my seven. When I left off on here I had the bucking down to just first gear and only when I would try to launch HARD or hit the gas hard. I went down to Naples FL over the weekend and the car had no problems at all!! Get back Sunday and didnt go anywhere so the car sat for like a day and a half. Got in it yesterday morning to go to work......first off it wouldnt start, after a few times missing with that I finally got it running. Alot of white smoke from gas filled the air. After letting it idle for a while I go to take off... stalled. Start her back up let it run for a minute or so....go to take off....died again. SO next time i started her I easied off the clutch got her rolling and now when I give her "ANY" gas what so ever it Bucks like HELL!!! If i let it sit and idle it doesnt seem to have any problems at all, even if i give it gas in neutral it revs without any hesitation. But anytime it seems to be under load it Bucks like hell!!! I have found that it will go in reverse and run fine too. SO I am boggled on what this could be and anyone I ask doesnt seem to know etheir. I have adjusted the TPS with no results. I have takin the filter off the AFM to check the little door and it seems to open and close freely. NEED some advise here on what to check!!
Thanx guyz.

Feds

Do a google for "Solving GSL-se Idle problems" PRint, read, love.

another potential problem is that the throttle is not returning properly. I had to put a heavier spring on my throttle return to get it to consistantly put the tps back in the right spot.

Try this: Set the tps (with the car warm, but off) then step on the gas, and let it off slowly, see if one light comes back on (not 2 or 0), then do the same thing, but just step right off the throttle, and see what happens.

r0taryluv

This doesnt seem to be an idle problem. Does the TPS have anything to do under load? I do understand it tells the CPU where the throttle is at. But even reving her up to 2k and letting out on the clutch makes the car want to die. I have adjusted this thing i dont know how many times. If everyone is telling me that my problem is involved with this little unit I will just go and get a working one from Orlando. Have someone over there that has one fro sale. But I just dont understand how before today the bucking would not happen untill i hit the gas Hard. If the TPS was indeed bad would it do it all the time as it is doing now? or was the semptoms of only happening when hitting the gas signs of it going bad?
Thanx for your reply

rototiller1

The tps is bad!!!, I'm going thru this right now, it reads out good when cold, as I drive it gets warm and worse, so I changed it out, was good cold again, warms up and goes bad, should just go buy a new one, instead of the junkyard, they are $171.00 at napa.

r0taryluv

Well I have to agree.... if anyone else is having this problem change the TPS... it is indeed bad. I drove order to a guy over in Orlando and he just got a TII motor put in his SE so he had the trottle body laying around. Put his TPS on which he knew was in working order. I am able to launch NOW!!! I am SOOOO fuqin happy!!! Fuel pump just came in today for the turbo setup. Now come to find out the 6 port acuators are not working... they are stuck shut. So I am ordering the intake gaskets to tear it all down and hope to free them up. I am going to wire brush everything to polish it all up too while its all off. I will take pictures for those who have never seen a tear down of the Trottle assembly on an SE. I wish I could have located a TPS alot sooner! but thanx for all your advise guys! This forum is full of good information!!

keep r0tating!