Marc01

Just finished my rebuild in the last week. Got it all back together. Runs nicely at idle. But, it is running RICH at idle. Used a voltmeter and found .8 volts at idle. Its bad enough you can smell the gas out of the exhaust and it burns your eyes. Worse, is boosting. This is boggling my mind. Problem is this. The idle will be ok. Take off, and as long as I stay light throttle the engine feels good. If I jump on the gas, it bogs down. Won't gain RPMS the more I punch it. Builds boost VERY slowly if I do this. If I keep it light, it will build boost after the transition and feel perfect running on the secondary. I can hear the primary spool up given enough time. I read a little bit of boost if I give it time to spool, but the bogging doesn't get any better. Also, sometimes get bucking, usually dropping the throttle just a little will take care of it. I'm really lost in this one. Seems like its dumping too much gas at low RPMs. I'm going to check my TPS tomorrow, but I'm not sure thats the problem. Above 4.5k the engine feels perfect. Responsive, boosts fine, makes plenty of power. I've swapped turbos to a known good set, thinking maybe the primary was blown on the set I had in the car. I've checked all of the vacuum lines. I replaced the fuel filter, because it felt like a clogged fuel filter. New plugs were installed 30 miles ago. Idle hunts, but I don't have the airpump anymore, and expected this. Its not bad, 600-800 rpms, and after running for a little while it evens out. I am pulling less vacuum than I expected, but just a little less. So I'm thinking maybe a vacuum leak, or maybe they aren't hooked up right. After doing some searching I think its also possible that a fuel injector isn't working right?

Any ideas? I could really use the help!
Thanks to any help,
Marc

Marc01

hrm ... no ideas??

I was looking for any suggestions.
Starting to get down to a time crunch, need the car to be running at 100%.

Thanks again for any help!

shawnhpv72

DO not boost on a rebuilt motor you have to break a motor in befor you rev past 4k and get on the gas or you can hurt your motor. the motor will build compreton as it breaks in then you will make good power. rotarys make poor power when rebuilt for the first 1k-1.5k miles.
piston motor makes good power after rebuild then there is a power loss after so meany miles. be good to your rotary before you hit 1.5k miles k
also the comp. will build up as the motor gets broken in.

Marc01

Sorry I wasn't clear. This motor already has 4k miles on it. I just replaced the coolant seals. All of the rotor seals were reused due to them being in perfect shape. So they are already worn together. If I'm wrong about this thinking, please let me know. I had an idea this morning, could be a loose connection on my map sensor or something, going to check it out in a few minutes. I'll keep everybody updated.

Thanks for the reply!

BobfisH

i had a similar problem, changing my spark plugs sorted it.

Marc01

I replaced the spark plugs before I put the engine in. They have about 30 miles on them. Don't think thats it .... keep the ideas coming!

BobfisH

not sure then, try an ECU reset for a start. Check MAP sensor connections and from then on check your solenoid lines.

If not then i suggest checking your turbo control solenoids, if you need to know which this is check out the vacuum map on my site, there is a link to it near the bottom of this page: http://www.face2faces.co.uk/RX7/howto/ratsnest2.htm

BobfisH

also check your wastegate actuator arm for rust. The only reason i can think that the turbo is building boost slowly is because the wastegate is stuck open, or the charge control is malfunctioning. The wastegate could be stuck open due to a rusty actuator arm (although unlikely) you can test this by having someone rev the car in neutral (punch the throttle till car hits 6k) and watching the actuators making sure they move. Also check charge control, could be that the actuator is stuck open causing both turbos to spin up at the same time even though only one is used.

Turbo control is a difficult one really, rule is test, inspect and test some more till you find something that dont work right. Could be a check valve, could be a solenoid, could be a split line - i suspect this is only something small though. I took the route of just doing my entire rats nest in silicon the second i had a boost problem to avoid this in the future.

Marc01

hrm, problem is not as bad, but still there. Found my Tps to be out of wack. And the plug was sorta loose. Readjusted and snugged the plug up, and the bucking and stumble in vacuum range were gone. Still have issues into the boost range. Found some concrete hard hoses and am replacing those now. Otherwise, the rats nest looks to be correct and in good working order. I haven't checked the injectors because they are quite a bit lower on the engine and would take the complete removal of the rats nest. I did jiggle the plugs on them to make sure they were snug, after replacing these hoses, I'm going to check the coils. It occurs to me that the wires haven't been replaced in forever, so that will be done. Plus I want to check the map sensor, not sure how, be doing a search on that in just a moment.

Just didn't want to be one of those threads where you find the exact problem you're having but no answers. Any further ideas as to the problem let me know. I'd love to hear theories. I'll do any troubleshooting you need. Oh yeah, also found that the restrictor pills were gone, so I went to the manual boost control. Set it 2 turns out, as rob got 8lbs of boost. I can't tune that until I get the car to boost happily. And no ECU codes at all. Not even reading the Double throttle control solenoid that I took out ... I should have a new pettit ecu soon. So I'm interested to try a ecu swap.

ok, back out to work!

framey

I had the same problems you're describing. Took in into the shop they replaced the EGR sensor and knock sensor and it fixed it. Could of been both but I doubt it, probably one or the other.
Sorry, cant be of more help just trying to suggest other things.

Marc01

Hrm, I don't know what the egr sensor is ... I know my knock sensor is good. I just took it out for a drive and still no fix. In desperation I've dumped some fuel injector cleaner into the tank, I seriously doubt it'll fix anything but I can dream. Next is to check the actuator rod length. I'm not totally sure how to do it, guess I'll be reading the Factory manual.

Is it possible for the timing to be spot on for idle, and stay that way as long as you don't jump on the gas? Ugh, so irritating. Drives absolutely fine under atmospheric (0 psi) conditions, builds up to 0 just as fast as it used to, but then stumbles. Sometimes I'll get to .2 bar. It eases up above 3k, doesn't build full boost above 4.5 but will get close to .5 bar. Not building full boost could be due to the manual boost control I put in, its the home depot mod. I found out there were no restrictor pills in the lines so I had to. Any other ideas out there?

Marc01

Oh and the knock sensor could do something like this. Mine is spliced and doesn't give normal readings but I ran it like this before the engine change without issue. It still registers knock and doesn't throw a code so I think the ECU is happy with it. The EGR (exhaust gas recirc) couldn't possibly have anything to do with boost. And is also not shooting a code. Thanks for the ideas though! Keep them coming.

framey

Whoops! Sorry, i guess it's not the EGR - What's the sensor called thats mounted on the downpipe? That was the one that was replaced.

DaveW

Oxygen sensor - that is only used by the ECU to control mixture at low loads/RPM.

However, if it is bad/connected wrong/not grounded correctly it could cause bogging, rich running etc.

No-Pistons-TT

this sounds just like the problem i was haveing check your map sensonr and the lines that it runs from. I was haveing the same problem. Also check your spark plugs just to make sure.

Marc01

Hrm, double checked all the hoses today. They all check good. All are running to where they are supposed to and all have a good seal. Still doing the same thing as SOON as I see boost on the guage. The blow off valve sounds very strange though. More of a whistle, it never did make a whistle before.

Checked my map sensor, and using the two outside wires it is giving me ~3.16vDC at idle. The book says its supposed to be giving 1.16-1.25. Now my engine being ported doesn't hold a steady 500mmHg, more like 400mmHg. The other strange thing, is as I rev it, the volts go down ... :-? The book has the map sensor hitting almost 4 volts at boost. I don't havea mityvac, but I can hit the throttle I know that there is less vacuum, shouldn't that raise the volts not lower them??

Marc01

Hrm, won't let me edit the last post but ... I was using the wrong wires. The map sensor is well within spec. Tomorrow I'm going to try putting in new spark plugs and wires just for the fun of it. This problem is driving me crazy. Thanks for all the help and keep the ideas coming if you can.

BTW, the o2 sensor is brand new, replaced when I put in the engine.

Marc01

Ok. Replaced the spark plugs. The idle is a little happier. But barely. Had to order the wires. But I DID get it out onto the highway. Did a little test. In first gear I can get full boost. Feels right, little hesitation down low but it picks up, then shift, going back to full throttle, and get like 1 maybe 2 pounds of boost through the whole gear, shift ... same ... Maybe the wastegate or bov are getting stuck open? I really am starting to think its not a fuel/ignition problem but turbo control. Anybody have any input?

PS
Also noticed at idle, my vacuum is barely moving up and down, like from 320-350 which is lower than it was. Normally, on this ported engine I was getting a rock steady 400 mmHg at idle. Sometimes before boost, just letting the car warm up, it will be at the 400mmHg mark, and thats when I get the closest to the boost being right. I think the wastegate or BOV are leaking. Still looking for confrimation ...

Cgotto6

iTrader: (8)

Have you checked all of the vacuum solenoids? Sometimes those can do weird things to the car when theyre not working properly.

dgeesaman

iTrader: (7)

Try the KOKO test. http://www.scuderiaciriani.com/rx7/boost_test.html

Also test to see if there is vacuum and pressure being stored properly. It could be as simple as a sticking check valve.

Dave

Marc01

I have checked to make sure they are all plumbed properly, and connected to the harness, but I have not checked each one individually to make sure it is working correctly.

Vacuum and pressure tanks are good. The pressure tank did have a sticking check valve, but its since been replaced. I was hoping with the symptoms some super guru genious guy would be able to tell me which solenoid to check. Guess I'll actually have to pull them and check them all.

I'll hit up the KOKO test tomorrow. I tried it once, to make sure the one on the y-pipe, I know its working. Check the actuator tomorrow. Thank God for the turbo timer.

So I guess this means I was off with my guess of wastegate or bov?

rxhead

Ignition coil?

dgeesaman

iTrader: (7)

It sounds to me like you have a sticking solenoid or check valve. The KOKO test is the easist test to perform for this and can be done without moving the car. This is why I suggest starting with it.

What you can do before tearing into the whole rats nest is to tee into the vacuum lines and do a road test, observing the output of the solenoid. You can do this for the charge control solenoid, charge relief solenoid, turbo control solenoids 1 and 2, vacuum tank, and pressure tank. I've done this with a second pressure/boost gauge, several feet of 1/8" vacuum tubing (the cheap stuff from a parts store is fine), and a plastic tee. For more details, see the post titled: "Date: Sat, 5 Sep 1998 11:41:28 -0500
From: "Steve Wynveen" at the middle of this webpage: http://www.scuderiaciriani.com/rx7/boost_problems.html

Whether rigging up the tee and doing several road tests is easier or harder than simply gutting the rats nest to test each solenoid individually is debatable. One thing is certain: you'll want a good Mityvac if you intend to test and replace solenoids.

Dave

Marc01

Ok. The Charge control is working as advertised. All 6 times.The turbo control however, isn't moving at all. So what should I be looking at troubleshooting?

dgeesaman

iTrader: (7)

Did you manage to get at least 3 psi in neutral before doing the KOKO step? If not, you might try charging the pressure chamber to 5-10psi with a Mityvac. (Pull the line coming from the y-pipe so that the check valve holds it in). Or, do it after a quick drive where you got at least 5psi of boost at some point.

BTW, I'm using this copy of the diagram: http://www.davidgeesaman.com/rx7/93v...lor.edited.jpg

There are two turbo control solenoids that drive the TCA - one for vacuum, and mounted on top of the ACV, and one for pressure, which is located in the rack (3rd from the front, I think). Generally, the actuator performs just fine, and it's the solenoids.

To locate which side is not working, tee into the line running between each one (vac = light blue on the chart, and pres = blue with red dots) and the TCA. Run the KOKO test, you should see full pressure or vacuum being applied and released with each key cycle. One or both may not be doing this properly. As well, it may depend on engine temps, so do it both cold and hot. (Hot is harder on electrical components, cold is more likely to show a solenoid sticking).

Dave