Claytons91

Alright I'm new to the Rx7 and rotarys. I got a 87 with turbo 2 swap, all emissions removed, pretty much stock with a street port, K&n filter, turbo inlet,walbro fuel pump.

I have not checked the compression, but I was told from PO that it was rebuilt 30k ago with pineapple racing kit.

it runs great, been having issues with hot starts, I just installed a fuel cut off switch.

What are some things I should look at?

satch

iTrader: (1)

What are all the issues w/the car? Is it more than just a hot start problem such as losing power above 4000 rpm.

Aaron Cake

iTrader: (1)

It's going to run rich with that fuel pump. Perhaps very rich after 4K if larger secondary injectors have been installed. Quite likely since it is a swap, the fuel pump is running directly off of 12V so it's making quite a bit of flow.

Also make sure the TPS is connected.

Claytons91

it has a high idle, around 1200 and the engine shakes, Could be bad mounts, but its not terrible.

also the injectors are stock, its a stock motor except for the mods ive listed, I'm sire the tps is connected I would check but I have no idea where it is lol.

and i'm o2 isnt hooked up, I cant find where it hooks up to?

also I do notice a big drop off of power at 6k, not sure if thats normal.

satch

iTrader: (1)

The TPS is in front of the throttle body and it rests against the throttle linkage. It has three wires and one is Green/Red. W/key to on and the engine as hot as it can get it should read 1 volt. There is an adjustment screw near the sensor which is about one inch long and encased in a spring.

Claytons91

Alright I'll check it when I get a chance, also I noticed I was at WOT 3rd gear and at 5k I was only pushing 3psi of boost....

normally its 5psi(which sucks) but it doesnt even hit that until like 4k.....is that right?

Claytons91

Alright guys update....I did a comp test using a piston tester, all I had, and basicly did an overall comp on the lead plugs, got 100psi or so on first rotor and 60psi on the rear(it might have been flooded?)

also I took the top intake mani off only to find out who ever put the motor together didnt bother to use a gasket....not even rtv, so I got that fixed and checked out all my injectors, and I believe my fuel pressure is too high.

satch

iTrader: (1)

What pressure are you getting and where did you check it? 60 psi on the rear rotor is poor so you might want to check it once again.

Claytons91

what?

Claytons91

did you mean fuel pressure? didn't really have a way to check it, I figured the walbro was upping the pressure.

satch

iTrader: (1)

Until you check the fuel pressure you won't definitively know one way or the other.

60psi on the rear rotor is very poor so you might want to check it again.

Claytons91

yeah I'll check it again, it seems to be running alot better, but it still feels like its lacking top end power.

satch

iTrader: (1)

The secondary injectors turn on at 3800 rpm so it could be an issue w/these injectors and the cause could be grounding related, which is very,very common on early S4's. ECU pins 3F and 3H are the secondaries and w/key to on they should both measure 12 volts. This tells you if the plugs are connected properly and that both wires in each plug are not pulled back within the injector plug.

diabolical1

iTrader: (3)

keep following Satch's directions to see if you can rule out as many things as you can as a cause. it is still the most sensible way to deal with things.

however, from here, it seems likely to be the compression. I had an engine doing pretty much the exact same things you describe (except mine was carbureted) - horrible hot starts, idled fine, 4000-ish RPM = Brick Wall, etc. - it turned out to be low compression.

Claytons91

its not a brick wall, its pulls great until around 5500-6k

satch

iTrader: (1)

Then where did the 4k part come into play?

Claytons91

i guess I was having a boost leak, buts its running better now, I tried setting my ign timing with a light but color markings are gone from the pulley.

satch

iTrader: (1)

There should be two grooves cut into the pulley to help identify the proper pulley position for setting the timing.

Claytons91

I have 4 on mine....I set my L1 to the one on the farthest right.

satch

iTrader: (1)

If you have four marks then you probably have an aftermarket pulley made by Racing Beat. I think the first mark on that pulley is -10 and the second is 0 so right in the middle of these two marks would be -5 degrees which is the stock position.

Claytons91

if i rotate to CAS to match it the motor will die,

satch

iTrader: (1)

When you set the CAS are you doing so w/the cap off of it so as to be able to look inside the internals of the CAS?

Claytons91

nope, but i will do that, I tried checking the compression again on the trailing plugs today and got about 65 maybe 70 psi overall.... not sure on what I should do.