frisbeedog

Hello everyone,

So my 7 bogs really bad under full throttle. I noticed during 2nd and 3rd gear that the car would have a serious hesitation during full throttle. It also lacks power climbing up through the RPMs.

I have recently changed:

1. Fuel filter- I changed this as a fix for the stalling problem. Seemed to help a little. i heard mention of a little filter next to the fuel pump, which i did not clean.

2. Spark Plugs- changed in the last 3000 miles. I have not pulled them yet to check the condition.

3. Cap, rotor, wires, ignition coils- all fairly new and reliable.


What do you fellas think?

gsl-se addict

iTrader: (3)

If you still have a cat(s), they may be clogged

Could be poor fuel supply too:

- clog in lines
- filter
- pickup screen in tank
- fuel pump on the way out

Here is what I would do. Start with a fuel volume test. Pull off the fuel feed hose in the engine bay and stick it in an empty gallon jug. Turn the key to 'ON' and either push the AFM door open or jumper the test connector (rubber boot connecter near AFM). Time for 1 minute. After 1 minute, the gallon jug should be half full or so. If it is quite a bit less, then it is time to start checking the fuel system. I would drop the tank at that point and check the screen and the pickup/return tubes. I've seen those get really bad.

If fuel flow is okay, then you know you need to look somewhere else. I would also check fuel pressure if you have a fuel pressure tester handy (I have one you could borrow).

Does it do this in all of the higher gears? Does powwer pickup after the initial bog?

frisbeedog

Power comes back only after letting off the gas.

Perfect_Weapon

Several years ago, I had a '83 12a stock fuel pump start going bad; had the same problems you seem to be having. It was really noticeable at interstate speeds, as the problem got worse in higher gears and higher rpms in those gears. The problem became more and more noticeable as the pump got weaker. Replaced with new OEM and problem was fixed.

frisbeedog

I noticed this morning that the fuel pump was whistling at me!

gsl-se addict

iTrader: (3)

Could be the pump or a blockage. My friend had clogged feed/return on the pickup tubes in the tank. The clog was so bad, that the car would only idle and would stall if you tried to drive it at all. The pump also was making a lot of noise since it was working so hard trying to get the fuel through that blockage. Do the fuel volume test. It is super easy to do. I bet you'll be low. On my friend's car, we only got a few ounces of fuel out over the 1 minute test versus the half-gallon that we should have got. We then retested at the pump to make sure the clog wasn't between the pump and the firewall. Same results. He had replaced the pump, so we knew that probably wasn't the problem. That left the tank. We dropped the tank and immediately saw the problem. Now, the tank (and hardlines) have been cleaned out and the tank resealed and now the car runs great.

Rx-7Doctor

iTrader: (13)

Also test the TPS per the FSM. I had the same issue and went through all of the Fuel pressure testing... The fuel volume and pressure were fine but I still got a used pump and changed it out anyways thinking maybe the pump was failing. Went back though all of the basic diagnostic checks and found the TPS was bad. Installed another one and set it to specs and the issue was resolved.

deadcatsrule

I am having almost the same problems with my GSL-SE at the moment,changed everything even the fuel pump.but not the TPS.fuel pump made it somewhat better .I'm going to say mines not the tank .when I was changing the fuel pump I left the gas cap off and gas ran out very nicely,so I don't think mine is in the tank.any ideas

gsl-se addict

iTrader: (3)

Still do a volume test. Really it only will take less than 5 mintues to do and then you will know your fuel flow is good instead of just guessing. All you need is a jug (about a gallon) and a watch to know when 2 mintute has passed.

frisbeedog

I have not had a chance to work on it yet. The gas tank and filter are both new. I will do the volume test for peace of mind, and also to prepare for fuel injector removal and cleaning.

gsl-se addict

iTrader: (3)

Another friend had this problem and had cleaned/repaired the tank and replaced the filter. The car had sat for sometime and he got it from a guy because it had a "blown headgasket". Turned out the pickup tubes were completely rotted. He replaced the tubes and cleaned the tanks. The car ran okay, but was showing power loss in the upper rpm range. We ran a volume test and it came up short (just like the other car I worked on). It turned out in this case the blockage was in the hardline. So even a new tank, filter, and pump can show these problems if the blockage is in the hardlines.

deadcatsrule

I had my injectors done last December by WitchHunter Performance.I don't know about anyone else but thats where I would send them.I have my problem down to just a miss once in a while above 5000 or so so the pump fixed most my problem.My car does not sit I have drove it all most everyday since I got it

frisbeedog

Maybe I have a blown headgasket!!!!

How did you go about cleaning the hardlines? I'm imagining blowing them out in the opposite direction of the flow. Is there a good diagram that shows the pickup tubes on through the hardlines?

gsl-se addict

iTrader: (3)

I wasn't there when he cleared them out. You could try compressed air to blow them out and see if they are clear. There are several short sections near the tank and those you could just remove and look through them and maybe run a wire through them to break up any blockages.

If your volume test comes back okay, then you don't have to do anything with the hardlines and the problem is somewhere else. So check volume and then check pressure. Once you have that info, let us know what you find and we can go from there.

mikeric

iTrader: (20)

If you are going to do the volume test, let the car run for 15 minutes to get the pump up to its operating temp. The aftermarket pump I had, would overheat and act wierd before it failed, but when cold it ran just fine. I have a wideband O2 sensor and aftermarket FPR with a gauge and under acceleration the fuel pressure would drop and car would run lean.

Since doing my turbo swap, I have my stock GSL-SE pump lying around if you do end up needing one.

frisbeedog

I'm such a slacker i still have yet to check the fuel pump. I did change over to a double sleeve alternator pulley hoping it was just belt slippage- it wasn't. What do you guys think about clogged cat? I have a new motor with a RB header into a new cat. Could i have clogged the cat in 4000 miles? I'm making a list of all the things I need to check when i start digging around. Thanks for all your help.


I did check the TPS and it was tuned correctly.

mikeric- I may still hit you up for your fuel pump!

wae

I'm in the middle of fixing almost the exact same problem on my 85 GSL-SE. Idles find, revs okay to a point, and runs okay during the warmup enrichment cycle, but once it hits normal temp, it just completely loses power. I've had similar problems with other cars and have always been told to look at fuel filters, bad gas, clogged lines, and such, but it has never been that.

In this case, however, my first test was the volume test and if I got 8oz of fuel in 60 seconds, I'd be surprised. After sitting for about a year, my tank is an absolute mess. The little cone filter in the fuel pump inlet was crammed totally full with what I can only describe as scaly crud from the tank. I dropped the tank and am going to take it to a local radiator shop tomorrow for a dip and some sealant.

There are two fuel lines on the left side of the engine. You want the one that is to the front of the car. Takes about 15 minutes, tops, to check it.