1991 KA stock, wont rev past 5K

[RatedR]

Had this problem before, but only when in gear....it was my 4th speed sensor. Now it does it occasionally and in neutral. Any info???

[RatedR]

Nistech, would appreciate any info you can give and please take a look at the other topic I 've started....Thanks~!

[NISTECH]

Nistech, would appreciate any info you can give and please take a look at the other topic I 've started....Thanks~!

Test your air flow meter to start. if it is not exceeding 4volts at wide open throttle it either has a poor ground or it is not registering properly. if its the later I recommend replacing it. I have heard of guys cleaning them but I dont know the longevity of it doing that.

[RatedR]

Thanks, I'll try that. But shouldnt a CEL come on for that? I'd think that it would be monitored by the ECU..... I'll swap it out with a MAF that works.

[NISTECH]

no it wont neccesarily throw a code if it thinks its reading properly. if it sees voltage between 0 and 5 volts and it varies it thinks its functioning.

[:: orion ::]

...and also check or unplug the 5th gear switch...if the ECU thinks you're in 5th all the time, the revs will be limited to ~5000.

- Brian

[RatedR]

I've had that problem before, but it wouldnt limit the revs in neutral....this time it does. Would that still be caused by the 5th gear sensor?

[:: orion ::]

Yes...unplug the 4th and 5th sensor, see what happens. If that fixes it...well, then that was easy.

If not, diagnose more.

- Brian

[RatedR]

Did this today, disconnecting the 4th gear sensor didnt work.... took a multimeter to the MAF connector that's connected to the ECU and found out the the middle connection didnt put out any voltage. the diagnostic tree i pulled from the AllData at school says I have to check the connectors labeled (f8) and (e9) i think. I have the proceedures but it says its a connection found in the engine bay......any ideas?

[NISTECH]

You should have 3 readings when properly checking your MAF 1 should be battery voltage 1 should be [at idle and pluged in] 1.3 to 1.5 volts and 1 should be less then .02v What do you have on all those wires?

[RatedR]

Got the 12V reading from the 1st connection, no reading from the others. I looked at the harnesses given from AllData and found a connection near the fender around the washer fluid reservior. Tried fixing that, no good. Read ECU codes, threw 12, MAF circuit. Tried replacing ECU and read codes. The new ECU threw 11 and 13, crank sensor and coolant temp. Replaced coolant temp, now the ECU reads 55 which is all good. Still limiting revs to 5K, dont know whats wrong now. I'm thinking when I tried disconnecting the 4th gear sensor on the old ECU, it didnt matter. Now on the new ECU, would it be apparent that the 4th gear sensor is the problem?

[NISTECH]

will it free rev past 5k rpm?

[RatedR]

no, in gear or in neutral it stops. I'm thinking that it might be the 4th gear sensor, but when the other ECU was still in it, the ECU was messed up and thought that the MAF was screwed. So now I'm thinking since the new ECU is reading all good, then it HAS to be the transmission switch. I've checked compression (180 min all around, 185 average) and the only thing that might be off is the transmission switch....

Also, nistech, i went and made the powersteering for my 240 a manual type by taking out the fluid. Should I run the rack dry or filled or with some fluid? Is there a way I can pack grease in the PS pump so that it wont go bad and I can plug the sucker up so it can still tighten the waterpump belt?

[NISTECH]

yea if it can free rev in neutral but not in gear I would say you might have something going on with one of the switches. use an ohmeter hooked to the 2 wires of the switch and have someone shift it in and out of fourth to see if it is working. If so thats not your problem.

Do not try to run you powersteering pump with no fluid in it. It will eventually seize up. not to mention the HP drain it will have on the engine. Do it right remove the pump completely from the car. fabricate a tensioner in its place to adjust the drive belt for the water pump. remove all the lines going to the rack cut the line going into the rack with the threaded end. flare the end of the cut pipe, install a hose from the pipe to the return port on top of it. fill the rack with fluid through the hose before you put it on. instant manual rack. I would go with a light gear oil in there but if you cant get all the p/s fluid thats in it out, put in p/s fluid instead. better off not to mix the 2 fluids.

[RatedR]

Well, I'm thinking the ECU should read a code if the MAF circuit is off, so I'm ruling the MAF out. The last time this happened to me (rev limited) it WAS the 4th gear switch, so I'm thinking maybe it went out again. I'll try what you said tomorrow in class cause we have shop.

Also, not to undermind your knowledge, but I spoke to one of the instructors at school and he says to run the rack dry. The fluid/air in there would just be a hinderance to the rack if not assisted by the pump. Speaking of pumps, how would I fabricate a tensioner? Should I take the PS pump and try to gut the insides? I was thinking of just filling it with grease to prevent it from seizing up and plugging up all the holes. Is that a good idea?

[NISTECH]

even manual racks have fluid in them to dampen shock from road input.

If you fill your resivor with grease I do not know what would happen. In theroy I could see it draging down your engine and possibly seizing up anyway. What I mean is either cut and fab yourself a braket that will bolt into the orignal p/s braket and get a adjustable tensioner pulley from another car. Install it in the place of the pump and match a belt to fit.

[RatedR]

for the time being, how bad would it be to plug the pump and fill it with ATF fluid? I'd still make the bracket (any ideas on where's a good place to start?) but for now since i'm pressed for time I want to just run it that way. I've f'd up the thread on the rack so i think i'm pretty much stuck with the manual type...