Scheibs

bought a 87 rx7 n/a for 300 from my bosses cousin b/c he just didnt want the pain in the *** anymore, needed fuel lines. trailored it to school and did the lines, started fine. on the way home the speedo didnt work, of course got pulled over. supposively the speedo worked before i got it but yea...didnt drive it much b/c i was waiting for the title to get to work from him, but one day me and a buddy took it for a ride, went around the corner....thats when hell started for me...it started misfiring and running for ****. idled like **** and would miswhen you rev it up(hear it thru air filter). puppied it back down to work and let it sit for the day. next day i started it and idled fine, anythign more than idle it went for ****, but when the engine warmed up, it ran for ****...did the plugs and wires and still did the same thing. then the next day the car would start then die, could only rev it to 3k if you tried then would die. so i was like ok, filter or pump..got it to school and the fuel pressure was lowish, did the filter and now its fine. car still starts and idles frine when cold but runs for **** when hot, if it starts....checked for cacuum leaks, small split in one, replaced it. checked the afm, its good. noticed the port air solenoid wires are corroted and broken off valve, but looks liek its been like that for a while, dont know if thats the cause...the vacuum is i think about 15 or close to that but bounces about 4 hgs. fuel pressure is about 45 at the motor and holds at 22 when car gets turned off. where i left off today i was checking the tps and when i would move the connectorm some relay would click, checked the connector and it was corroted of course and cleaned it a lil but prob not good enough.

Yesterday the regulator wasnt returning fuel in the peginning of class, but at the end of class i tried to start it for a hail mary and it did and the regulator was returning gas, then engine wasnt hot at that time tho.

This car starts really cold when it is cold, idles perfect when cold but anything more than idle its bad.

The car is really hard to get started when hot, you be lucky to get it started when hot, and if you do, it still misses when u give it gas.

I really need help with this!!!!

calpatriot

If it started when you did a corner, it could be a loose wire/bad connection on a sensor. Or, maybe its just coincidence. In any case, the first thing to do is check for trouble codes. See...
http://www.teamfc3s.org/info/article...odes/main.html
to make the $3 code checker.

If there are no codes, then check for closed loop operation. Search this forum for my posts on the 'green lamp check.' Sometimes the ECU fails to sense that the oxygen sensor is not there, and tries to adjust the mixture based on a non-existent O2 sensor signal. The heavily rich mixture fouls up everything, and then the car runs terribly, but there is no trouble code.

If all that is working, try setting the idle speed and mixture per the FSM procedure, check timing and advance, and check and set the TPS.

The port air solenoid is unlikely to be involved with this problem; it injects air into the exhaust.

You can also check for an exhaust restriction by trying it with the O2 sensor removed, and leaving the hole open. If that causes the problem to go away, look for clogged cats or other exhaust restriction.

The hot start problem could be due to: low compression; leaky injectors; poor performance of the water thermo sensor, of the AFM.

Scheibs

no codes showed up, the tps swept perfect no glitches or anything, the collant tep sensor is good.

but the thing that is bad that i found today was the intake air temp sensor if that will do anything. It was constantly reading cold air was coming in (5.3K ohms) even after running for a long time while runnin for ****

also checked the volume that the pump was putting out, was a little low

Unfortunately i had to drive it 15 miles home so i could work on it this spring break, it was runnin so rich my buddy couldnt stay behind me on the freeway. I think it might be sticky injectors but thats just me!

HAILERS

Clogged fuel stainer in the fuel tank. Done.

Scheibs

the fuel pressure is 45 at the engine and incerases when you rev it so its workin fine, its actually running rich.

calpatriot

The intake air temp sensor may be responsible for it running rich.

If a new part is too expensive, there are several rx7 salvage yards that do a good job by email/mail order. I use Apex Auto Parts.

Fix the sensor, and then try again.

Check for closed loop operation at cruise.

Scheibs

how should i check the closed loop operation?

n yea i figure that sensor could be a main reason for the richness, but idk if it explains it when its cold that when i try to go its still missin, but we will see.

i found one off of ebay for like 20 but i need to wait for my paycheck or to come across some cash to get it(this thing is putting me broke!)

HAILERS

*******, went around the corner....thats when hell started for me...it started misfiring and running for ****. *****

A classic sign of the fuel strainer in the tank varnished over, especially if its a left hand turn you make.

***************fuel pressure is about 45 at the motor***********

Stock fuel pressure is approx 28psi at idle, I mostly see 31 psi. IDLE is defined as 750-800 rpm. IF you still see 45psi at 750-800 rpm, then find out why there is no vacuum going to your FPR.

When adjusting the TPS and click being heard is as normal as can be. Adjusting the TPS causes the ECU to put a gnd on either the switching or relief solenoid hence the click. That's one of the purposes of the TPS.

********This car starts really cold when it is cold,******* That's interesting. What does that mean?


Car won't start when hot. Usually because of low compression. I'd suggest you make a fuel cut off switch to overcome that problem in the short run.

Scheibs

yea it was a good left hand turn i took when it went to ****

could it just be the FPR bad? i tested it and when you removed the vac line it went up to 50 psi and dropped back down to 45, when you hooked a vac pumped and applied it, it would go back down to 45

the car idles and starts really cold i meant, but when you try to go, it just loads up

the click on the tps was doin it when i was wiggling the connector tho, not idling or anything

HAILERS

Just follow the FSM. Battery fully charged. Jumper he fuel pump check connector. Turn the key to ON, engine OFF. Pressure should read approx 37-39 psi.

Then idle the engine. Pressue should be 28-31psi.

45psi is too high especially at idle.

Or you could just warm up the engine fully. Look at the pressure at idle.(should be approx 28psi......then pull the vacuum line off the boost/pressure sensor and plug that line and see what the pressure is at idle now (should be approx 37- 39psi) now with no vacuum on the FPR.

Pull the fuel pump strainer off and replace it. It may LOOK clear, but I be its varnished over. Or soak it in acetone bought at HOme Depot for a few hrs and blow it out. Then go drive it around a left hand corner and see if it still almost dies/stumbles etc. If it still does.........I was wrong.

Only time I ever saw 45psi on a stock FPR was when I had a MittyVac on the FPR and applied pressure to the FPR. About 50psi is just about all it would rise to.

Scheibs

im new to these roataries so...

FSM?

so when i pull the vac line off the pressure sensor then plug it into the FPR? idk that sentence didnt make sense really but thats what i got out of it.

I ordered a walbro 255 for the car, when that comes ill put the new strainer on at the same time since ill have it out lol

HAILERS

Yeah, that was a mess. I meant to say......idle the fully warmed up engine. Look at the fuel pressure. Should be approx 28-32psi. Then while still idling, pull the vacuum line off the FPR and plug the vacuum line so the engine does not stall. The pressure should be 37-39 psi as seen on your fuel pressure gauge.

FSM stands for factory service manual that can be downloaded on this site. See the FAQ thread at the beginning of this site.

Sounds to me like this car already has a Waldo and that pump is over riding the stock FPR. Just an opinion. Just saying the fuel pressures you mention, all sound higher than normal.

Scheibs

i've tried the removal of the vac line while its hot and running(missing bad) and the rpm change is none and the fuel pressure goes up 5 i think or goes down 5, i think its up

it may have a walbro on it idk, but if it does ill just return the one i got but ill replace the strainer

n i was gunna try to do that preload on the fuel pressure, but the battery was dead so i wasnt able too lol.

calpatriot

It's really simple. You make a 12v LED (regular LED in series with a resistor, i.e. 1k ohm - 2k ohm, to keep the current at 12v down to within the limits the LED can take). Hook it up to a two conductor wire, or two wires, which end in male spade connectors. The LED works only in one direction, so test it on the battery terminals, and see that it lights up, and note and mark which lug you put on the +12v terminal of the battery to make the LED light up.

Hook up your LED test set such that the +12v lug goes to the top center connector in the 6 pin test connector in the left front of the engine compartment. The negative lug should go to the bottom center connection in the 6 pin green connector.

I define top as the side of the connector that has the latch on it.

The LED should be off at idle until the car warms up. After several minutes, it should light up (showing that the oxygen sensor has reached operating temperature).

I made my test set long enough to hook it up and remote the indicator (LED) into the cockpit, so I can monitor the LED under driving conditions.

The LED goes on and off as the ECU sees a rich and lean mixture signal off the O2 sensor.

Once the car is at temp, the LED should be on during idle, and acceleration. It should be off (lean) during deceleration. Most importantly, at steady rpm cruise (say, 2000 rpm), it should flash on and off about 8 times in every 10 seconds. This indicates that the ECU is going into closed loop (actively controlling the mixture) during cruise.

If the LED indications are not as above, you need to find out why and correct the problem. Be especially attentive to what the LED is doing during any missing or drivability problems.

If the LED is not flashing during steady state cruise, the ECU is not going into closed loop ops, and without that it has no way to adjust the mixture. Usually this is caused by some problem with the O2 sensor circuit: bad sensor, connector not connected, wire open, wire shorted, bad connection at the ECU, or failure in the ECU.

If the ECU is not seeing the O2 sensor signal, it runs in a default rich mode, which allows you to drive, but it often will foul up the plugs, leave more carbon deposits in the engine, and overheat/destroy the catalyitic converters.

n yea i figure that sensor could be a main reason for the richness, but idk if it explains it when its cold that when i try to go its still missin, but we will see.

i found one off of ebay for like 20 but i need to wait for my paycheck or to come across some cash to get it(this thing is putting me broke!)[/QUOTE]

HAILERS

Well.......idle till warmed up and read the fuel pressure at idle Should be 28-31 psi at idle with the vacuum line on the FPR.

Turn the engine off.

Remove the vacuum line on the FPR and plug the line.

Start and idle the engine. Pressure should be 37-39psi.

Pressure goes up from 28psi to the 37-39 psi because there is no vacuum on the FPR no 'mo.

This a 86-87 car? non turbo?

Scheibs

or i could use my schools scanner and look at the signal coming from the o2s and see if it goes lean/rich like it should?

the fuel pressure is never that low, its always atleast 40-45 with that vac line on

its a 87 non-turbo

HAILERS

Is that a stock FPR? What is the approx idle engine speed?

Scheibs

stock for what it looks like, when its goin rough, bout 600-700, when its idling good its between 1000-1200

calpatriot

You don't need a scanner to do that. All you need is a simple voltmeter. The sensor voltage should read above 0.5 when rich, and less than 0.5v when lean. Typical values might be 0.7 and 0.3...

If it is hunting back and forth between those values at steady cruise, the ECU is doing closed loop like it should.

The advantage of checking it with a lamp at the test connector is that this signal come from the ECU, not directly from the sensor. Thus, if the monitor lamp signal is behaving properly, you are checking not just the sensor but also the wiring and the ECU.

For example, if the O2 sensor voltage is a steady rich value (i.e. 0.7v), but the lamp is off, then you would know that the ECU is reporting a lean mixture while the O2 sensor is reporting rich. This would imply that the wiring to the sensor is open, and the ECU is seeing the 0 volts signal and interpreting that as a lean condition when the car is actually running rich.

The two signals (monitor lamp and O2 voltage) should agree. If not, there is trouble in the sensor circuit or the ECU.

turboIIrotary

iTrader: (9)

bounce as in tick? if that the case then your engine has a cracked side seal or something like that this will also cause a rough low idle but will smooth out when goin into the 1k.

Scheibs

a voltmeter wont catch all the variations fast enough at times tho, but ill give it a try after spring break b/c i dont have any of the tools to do so lol

HAILERS

Possibly misrounted vacuum lines on the FRONT of the dynamic chamber. Three hose there. One is large and can go but one place. The other two might be swapped around and that would cause a idle problem.

Or there's two small vacuum lines on the back of the chamber that go to the purge valve if I remeber right. Might be off at the back or cracked or/???

One small vacuum line comes off the left side of the chamber and feeds part of the vacuum rack. Might be off or???/

The Large vacuum line on the front feeds the OMP spider under the manifold, which in turn feeds air to the top of the oil injectors. One of those lines might be off/cracked etc.

The fuel injectors have rubber grommets b/t them and the *block*. If rock hard they can leak air and cause idle problems.

The EGR can have a internal leak that can cause idle problems. Or the vac line to it leaking can cause problems.

A can of starter fluid sprayed around the intake area can help you find leaks.

I'd borrow or buy a cheap timing light and make sure the timing is right. RPM MUST be well below 1100rpm when checking the timing.

This car have the airpump and ACV installed with belt?

Harbour Freight sells a very good for the price, digital meter made by the chicoms. Called or made by CEN-TECH

Scheibs

ive smoke tested the intake at school, and the only leaks i found was the line from the motor to the pressure gauge was cracked so i got a new one, and the other was i think around the throttle lever on the upper was leakin. that the only leaks i had pop up...i was gunna take a look at the injectors to see if they were stickin or not to see if that was my problem

n yes the car has the pump and the belt on it

Scheibs

would a s5 air control valve setup bolt onto the s4 and the sensors work too?

Scheibs

put the walrbo pump with the new pump filter and the intake temp sensor, now ive only got it to start once, but hanvt got too otherwise, wth is goin on? could it be the pressure reg sending too much gas thru the injectors or are the injectors just bad?