Mr.JTurboII

I've finally got my 88 turbo on the road this weekend and it didn't go so well. not sure how to explain it but in first and second there is slight hesitation at around 3800 but its not too bad. once you get in 3rd, at around 3k it just falls flat on its face and with wont go. the boost gauge goes crazy. once its pass 4k rpm then its driveable again. shift to 4th and 5th same thing. yesterday i noticed that if i try to pull in 5th. the boost gauge went up to a lil under 1 bar and it wont rev past 5k. im now paranoid because i know the car doesn't have the supporting fuel mods to handle that much boost. so i've taking it as easy as possible trying not to go past 3k for now. What should i do to fix this?

dwb87

iTrader: (22)

What modifications do you have?

1986rx7se

i had a similar occurence once, and so have a few others. the fuel tank had rust deposits, and the fuel sock at the bottom of the pump got clogged. i cleaned the sock and it happened again after a few hours of driving. had to totally remove the tank and drain it, clean it, and reinstall. the pump is very easy to remove. the carpet in the hatch area needs to be pulled up. i believe there are 4 screws to remove on the left hand side. this access cover lets you get to the 6 screws that hold the pump in the tank. make sure you have a good screwdriver because the screws strip easily. i believe they were phillips screws. remove the pump and look at the sock/filter. if it appears to have a sludge type mess on it, spray it off with carb cleaner or a similar product. reinstall and test drive. this will help determine if it was the problem. if so, replace or clean the tank. ive also heard of the baffles rusting out in the tank. hope this helps. its a very easy fix and a cheap one also.

another thing to check is secondary injector operation. they kick on at 3800rpm. sometimes they fail. let us know how you made out!

J5sense

iTrader: (3)

I had the same problem of the fuel sock becoming clogged. you just pull the pump and popp on the new sock. my sock looked fine but when i replaced it it fixed all my hesitations. they where more present when i would turn or accerlate. (anytime the gas would move in the tank)

they are as low as $4.00 on rockauto.com for the cheap ones. i went with the denso one.

http://www.rockauto.com/catalog/raframecatalog.php
DENSO Part # 9520043 $14.20

FC_fan

iTrader: (2)

don't mean to thread jack but I have a similar problem. I drive a 86 na and do not have the split air pipe that operates the 5th/6th ports which comes on at 3800rpm also so they never open. car was fine going to 7k rpms for a while but all of a sudden it starts just dying off after 3800? only does this now and then and usually in 1st and 2nd but has done it in all gears including 5th (testing things out on highway). I'm wondering if its my tank or just my secondaries dying now. I was told that my secondaries are dpendnt on my 5th/6th ports working. but then why would it rev to 7k before?

1986rx7se

FC fan: the tank is super easy to check, and a great place to start. Shouldn't take more than a half hour to access and diagnose if its the cause. I had an 86 n/a without the split air pipe connected and it ran fine without it. I'd guess you have a fuel delivery problem. Check the tank first, and then move on to secondary injector wiring/injectors.

Mr.JTurboII

I changed the sock, it looked dirty and i ordered a new fuel filter. took for a test run this morning, it ran soooooo beautiful with the new sock, i would of never thought to change that. thanks guys. sadly I've developed a major exhaust leak in my fun, so it will be experiencing down time again lol

satch

iTrader: (1)

Pin 3F and 3H are the ECU pins for the secondary injectors. Both should have 12 volts w/key to on. If so, this proves the injector plugs are connected properly to the injectors. You also might have a grounding problem that causes your symptoms. If this were the case, you could add an extra ground to the Pressure Sensor or at the ECU (pins 3G, 3A, 2R and 2C).

Since the secondary injectors come on line at 3800 rpm w/load then there should not be a problem when the car is reved while idling. If it revs fine while idling then it rules out the primary injectors but not the secondary injectors. You can place the car under load by disconnecting the wiring to the TPS and removing the vacuum hose to the Pressure Sensor. This will allow you to rev the car in neutral but under load, so the secondary injector operation can be observed.

FC_fan

iTrader: (2)

^thanks for the help guys. its not the 3800 hsitation, I just hit a wall like applying the brakes (if florring it in 2nd) and then the power just dies. (i.e. accelration power, not electrical ). hope its just the sock but its new along with pump 2 yrs and 20k miles ago but still could be. my car floods if I leave it sitting for 2 days w/o starting so maybe it is my injectors. I'll check soon all the possibilities.

dwb87

iTrader: (22)

To see if your fuel injectors are stuck open...

Strap/secure the injectors to the fuel rails. Unbolt and remove the fuel rails. (There's an illustration of this in the 87' FSM. "Fuel and Emission Control Systems" 4B-74) - Obviously you do not remove the injectors or any of the fuel lines. Be sure to set some rags or something under the injector's fuel outlet nozzle, to absorb fuel in case they are stuck open. Jumper the yellow fuel pump test connector at the passenger side strut tower, near the AFM. Turn the key to "ON"... Not to "START". You'll hear the fuel pump running... Now go check the injectors to see if they are spewing/leaking.

If you do not have a Factory Service Manual, here's a link to some FSM's: http://foxed.ca/index.php?page=rx7manual#secondgen

slpin

iTrader: (9)

swap injectors around... primary with secondary, secondary with front... any change in behavior? this will rule out your injectors....

if it improves? replace all 4....
why? they are both as old as each other - and chances are - all are at the verge of failing

Rickyyp

iTrader: (3)

i am having an issue with hesitation as well. i replaced the my fuel pump sock and all filters. its not fuel cut because i have a aftermarket gauge and its only going to 6psi. After changing the sock it hit the 5k wall but pushed through after a couple seconds.

i did as described above and the car rev'd out completely fine. my afr's were between 10-14 when i rev'ed it up.

does this rule out my injectors and point towards a grounding issue?

satch

iTrader: (1)

Not familiar w/fuel ratios but your exhaust could be clogged, faulty Boost sensor and perhaps grounds as well.

Rickyyp

iTrader: (3)

oh sorry it just means that it is running rich and has plenty of fuel. so i think my secondaries are working properly. i have a full exhaust with no cats. im not using the boost sensor. unless you are talking about the map/pressure sensor ??? i get confused by the two.

satch

iTrader: (1)

Boost sensor/Turbo car, Pressure Sensor/NA car. Same thing.

Rickyyp

iTrader: (3)

fixed it was the injectors. thank you so much guys