car looses power at half throttle help
 

i posted a few weeks ago and and well its not the fuel pump

i have a 90 rs 3.1 v6 every time i get to half throttle the car dies out and looses power... even in park or neutral it wont rev past half throttle i replaced it with a brand new fuel filter and pump..... could it be bad spark plugs? i need help this cars becoming a problem for me

Re: car looses power at half throttle help
 

How would it be spark plugs? How about a bad Throttle Position Sensor? That makes more sense to me.

Re: car looses power at half throttle help
 

mayb but theres no check engine light.... and my old car (91 talon tsi) had a bad tps and didnt have that problem ( i said spark plugs and wires because thats what the shops trying to tell me) what about fpr? and how can i check that? im mainly just looking for things that could cause this

Re: car looses power at half throttle help
 

Why are you referencing a Mitsubishi to work on this?
Why would the SES light come on if the sensor failed in such a way that the computer believes you lifted your foot off the go-pedal?

Re: car looses power at half throttle help
 

idk but i admit i know nothing about these cars... but im willing to learn

why am i referencing a mitsu is because that was my old car.... but its not like i lifted my foot of the gas........

tonight the car kept turning off on me........ i have a shop that tells me its the plugs and wires? all i know is i need help

Re: car looses power at half throttle help
 

First, I'm not racist. But I believe that the Japanese thinking for programming their engine computers is very different from the thinking of the people who designed our junk. Your direct logic doesn't work. I assume you're still using the same shop as when you had that DSM car?
If they claim it's plugs and wires, then they're thinking that the increased cylinder pressure atbove half throttle is blowing out the spark. If that were the case, that would be a weak spark, which points to low voltage to the coil, or a bad coil.
But if it was ignition, it wouldn't just be above half throttle. You would have misfires and hard starting, but it would do it all the time.
I didn't say you were lifting. But if the TPS has gone bad in such a way that it tells the computer that you lifted, well, the computer is simple, it's not going to light the SES bulb when it believes you simply lifted.
Why are you opposed to investigating the TPS?
What else, realistically, could cause your symptoms? Noone else has contradicted me, so that must mean they don't have any good ideas different from mine. I half wish someone would.

Re: car looses power at half throttle help
 

On my Camaro everytime I would go past half throttle it stopped producing power and felt like it was about to die. I replaced all my plugs and wires and it runs good as new. If you want to make sure it's the plugs pull one out and inspect it for build up. Plugs aren't too hard to do so please don't take it in and waste your money on having someone else to do it. It's a pretty simple procedure and the only "fancy" tool needed is a spark plug socket, you'll also need a spark plug gapper. (.035")

Re: car looses power at half throttle help
 

If your plugs are bad, replace them. If the electrode still looks decent and they're not fouled or anything, then your problem is probably not your plugs. Same goes for wires, check the resistange on each one and check for any damage, if they look good, again, not your problem. IDK why you replaced the fuel pump w/o checking if it was bad first, but I guess that now it's eliminated...

Re: car looses power at half throttle help
 

Do you still have the stock catalytic converter on that car?

Re: car looses power at half throttle help
 

i never took my dsm to the shop did everything my self.... those cars are made so beautiful its easy to get to everything..... i replace plugs and wires on my dsm before i know how to do that not sure where everything is on these engines i have a gapper.... what spark plugs are best for these cars (90 3.1 v6)..........and yes i believe its the stock cat...... i replace the fuel pump because thats what some people here said it was

Re: car looses power at half throttle help
 

Most people say Delcos. I went with Delco part #R43TS when I replaced the plugs in my car. They cost about $2.50 a piece and I have no complaints.

Re: car looses power at half throttle help
 

Could it have something to do with the Fuel Pressure Regulator? When he opens the throttle, he's going to lose vacum, and vacum controls the FPR. He could be flooding out the motor, and I don't think the computer monitors the the fuel pressure.

Re: car looses power at half throttle help
 

a few things.... when tighting the sparkplugs how many turns should i turn it?.... and what would be the best way to check if the fpr is bad??

Re: car looses power at half throttle help
 

I've always have been told that spark plugs should be just more than hand tight. And Probably the best way to check the fpr would be with a fuel pressure gauge. Prime the system (put the key into the "run" position for a couple of seconds) and the pressure should be in the 45 psi range (no vacuum). Start the engine and it should drop to around 30 psi at idle (lots of vacuum) if I remember correctly. The more you open the throttle, the less vacuum the motor produces and the more fuel pressure at the rail. If it checks out, it isn't anything before the fpr, if it doesn't than the fpr might be good, and something before it could be wrong.

Re: car looses power at half throttle help
 

A few years back, AC Delco changed the length of their spark plugs. I'd been running them in smallblocks for years and years and all of a sudden I started burning plug wires on headers...in several cars. I wasn't the only one who had this problem. That's when I called AC Delco and got an absolute stonewall. All they'd say was that their plugs were designed to fit stock vehicles and essentially if I was running headers, tough. They wouldn't even admit that the length had changed.

At that time I had photos of the old and new ACs, Autolites, Champions and Bosch plugs. I had 'em on my web server, but I took that section down and can't find it now. Whoops. I take that back. I just found the photos:
http://chevyasylum.com/acdelco/Welcome.html

Anyway, I went with Bosch Supers at that time and I've never had a plug failure (or burned wire) since. I use whatever crosses from AC R45TS (usually 7585) except in my race car where I have to use Accel shorty plugs.

Re: car looses power at half throttle help
 

Weren't you the guy who had problems with the leaking fuel line? If you didn't get that fixed, and your fuel pressure is still low, you're going to have problems above half throttle because there isn't enough fuel to feed the engine. Check the fuel pressure and the color of the spark. Either or will tell you what you need to do.

And I agree completely with the AC/Delco plug length change... I still have a couple of the old Delcos I got in my 2.8 when I bought the car, and the new Delcos are definitely shorter from the metal shell out to the plug terminal.

Oh, and the general rule for spark plugs is hand tight plus about 5 minutes on the clock with a socket.

Re: car looses power at half throttle help
 

5 min with the socket? and yes i snapped a fuel line but thats fixed and after a few days the car stopped starting and was told it was the fuel pump so changed that and nothing.. i eneded up having to cange the dizzy and rotor... and my problem is after half throttle not before.. but hafter the car warms up a bit its not as bad..... and also i thing it might be the plugs because i am hearing misfires when driving. either way when i get the time im going to change those because im 99 percent sure its the origanal plugs

Re: car looses power at half throttle help
 

Stock Multec injector coils shorting out?

RBob.