Renix Issues

Hello everybody, this is my first post on , Im fro Bremerton, WA and Ive lurked on here a decent bit. I am on the local PNW boards. I have an 89' wagoneer. 4.0/AW4/242, Locked 44 rear, LSD 30 front, 4.10's, 31's etc.etc.etc. lots of little custom built pieces all around.

So since September Ive been having some bad running issues. my fuel pump was whining really bad so I put a new one in. That pump was DOA so I exchanged and got a new one. a week or so later I started running like poo. I am putting 14-15PSI on the fuel rail. new wires/plugs/rotor/cap/fuel filter/air filter/TPS/IAC. so theres a little background.

THE ISSUE:

First off, it is very hard to start, typically takes 10-12 seconds of cranking, and then may die right off or may idle rough for a second then idle.

So it will appear to idle ok at this point, but the second throttle is applied it will either bog and die FAST, or if I jiggle it around and feather it I can bring the RPMS up and after a few seconds it will bog out and die.

the MAP vacuum line had a small hole which I repaired, and both lines running to the vacuum canister under the battery were broken and whistling, and they have a temp. fix to see if that was the issue, but as far as I know they are just for heater control anyways?

The coil pack has the two leads, +/- and it has a small male connector in between the two. There is no lead connected here, but I dont recall there being a wire there previously.

so what should I look at. What tests should I perform on what sensors. or what vacuum lines should I look at.

Thanks guys!

-Maxx

OK - I just want to make sure we're all on the same page...

1) When you say you're "putting" 12-14psig on the fuel rail, I'm assuming that's a test figure, with the engine running? And that you're checking it with a test gage on the Schrader valve? What pressure do you develop with the engine OFF and the key ON, and with the engine RUNNING and the vacuum line to the regulator disconnected and plugged (should be close to the key ON/engine OFF figure.)

2) Have you a copy of the RENIX EFI manual? It's available at Pirate (in BillAVista's tech goodies,) on the strokers group (groups.yahoo.com/group/strokers|files|Technical Archive|89Jeepfi.pdf. Handy little beggar, I've found...)

3) Note that a "long crank" start is actually fairly common with RENIX. Why? Because the chassis and ECU ground through the engine block (by way of that silly little ground strap from the cylinder head to the firewall...) and that makes it easy for the ground plane to get contaminated. RENIX won't start firing ignition or FI until it sees 300rpm at the CPS and it looks for a valid SYNC signal - if the grounds are shonky, that will contaminate both signals rapidly (as well as the MAP, TPS, HEGO, IAT, CTS, ...)

There should be no wire on the centre coil terminal - I don't know exactly why it's there offhand, but I know it's not used.

Those are my first thoughts - but I'm on the way out the door, and don't have much time for deeper thinks - I'll have to get back to this later to-night.

1) Yes thats on the schrader valve on the rail. I will test the other figures when I get home tonight.

2) I actually discovered the PDF like 2 minutes ago, gonna print and bind it here at work, hopefully today and before I leave!

3) I know the long crank is common and it used to fire up after like 2 revolutions, but now it goes on and on and on and on. I have redone all my wiring and added several heavy grounds.

Hey... i chased the same problem on my 88 for months, and turns out it was a bad EGR valve... I disconnected mine, and plugged the vacume lines, and she runs great at start up ever since. Before with the bad EGR, she would die right out as soon as I put it in gear unless I fiddled with the throttle, then if I kept her running, she would pop and cough and act all kinds of upset for a few seconds before finally settling down. after the engine warmed up she would be ok, but those start ups were a pain.

all you did was plug the EGR vacuum lines? could I just pinch the lines to diagnose?

maxxpehling said:

all you did was plug the EGR vacuum lines? could I just pinch the lines to diagnose?

Click to expand...

The EGR gets it's vacuum from a solenoid on the left fender inside the engine bay towards the front. The computer turns the solenoid on and off, at idle the solenoid should be closed. The solenoid is default open, when the power is interrupted it defaults open and will mess with your idle and can cause the motor to stall at low speeds. The EGR itself sticking open or a broken spring in the EGR can cause the same.
The MAP needs a good vacuum line and the vacuum line needs to be plugged into the top opening on the rubber stopper on the passengers side bottom of the throttle body. Blow through the vacuum line and check for stoppages, plug one end and suck to test for vacuum leaks in the MAP vacuum line. Bad (or no) MAP vacuum can make it run like crap. Hard to start, maybe idle and accelerate very poorly if at all. Though I've had a borderline CPS, display almost the same symptoms.
14-15 PSI on the fuel rail is way too low. You can pinch the return line after the regulator and see if the pressure goes up.
The only fuel pump problems I've ever had were the a bad ballast resistor and on another occasion a cooked connector in the harness that severely cut down on the amperage to the pump, voltage tests were fairly normal. Though I'm guessing the cooked connector was a one off problem as nobody else has ever mentioned seeing it before.
Jump the ballast resistor (located on the same inside fender as the MAP vacuum solenoid) and see if the pressure goes up, just to eliminate this as a possibility.

Forgot to mention the new ballast resistor, the old one was looking pretty sick on the backside. Of all nights I think my solenoid on my starter took a crap. But my pressure on the fuel rail in the on position is 16-17 and gradually drops to zero. Also, the MAP hose runs to the bottom of the gromet on the TB side but its always been that way... Plus its a pretty rigid line and is formed to go there

maxxpehling said:

Forgot to mention the new ballast resistor, the old one was looking pretty sick on the backside. Of all nights I think my solenoid on my starter took a crap. But my pressure on the fuel rail in the on position is 16-17 and gradually drops to zero. Also, the MAP hose runs to the bottom of the gromet on the TB side but its always been that way... Plus its a pretty rigid line and is formed to go there

Click to expand...

The MAP line is right. That fuel pressure dropping off like that sounds like a leaky injector(leaking to the inside at the nozzle). If you still have the OEM injectors you need to change them out before you burn that XJ to the ground! The original injectors will start leaking to the outside without warning and you know the rest of the story.

Concerning the EGR bypass...
The way I did it was easy, and the test was the fix. The above mentioned EGR vac line goes from the fender to the EGR valve. (a disc shaped part at the exhaust manifold) I removed the whole vac line, and cut 2 little pieces off of it. I sealed one end of each little piece creating 2 "caps" that I used to cap both connectors that the vac line came off of. Presto! The EGR valve was effectively bypassed, and she ran smoooooth! Others have done extensive work to "delete" the EGR including unbolting the EGR from the manifold and rigging a metal plate to seal it off. The way I did it, if it ends up not fixing your issue, you have only cut 2 little pieces off the original line, and you can just replace the line.

EDIT: After reading your last post, you DO have a fuel pressure issue... After fixing that, if you still have stumbling right after you start it, I would test the EGR delete proceedure.

The fuel is draining back into the tank, I can hear it out back. So for now can I just pinch the line between the egr solenoid and the egr to see if it is in fact the egr? Still banging my head over this starter issue..... Its just clicking really loud.

maxxpehling said:

MAP hose runs to the bottom of the gromet on the TB side but its always been that way... Plus its a pretty rigid line and is formed to go there

Click to expand...

Sorry my bad, I guess you can tell I've screwed that up before, the main reason I pay any attention to it at all.

I've had rub throughs (chaffing) on the bottom of the MAP vacuum line before that were barely noticeable.

Mine had some rub but it holds vacuum

maxxpehling said:

The fuel is draining back into the tank, I can hear it out back. So for now can I just pinch the line between the egr solenoid and the egr to see if it is in fact the egr? Still banging my head over this starter issue..... Its just clicking really loud.

Click to expand...

I would remove the line and cap it off. I wouldn't just pinch it. it took me all of 5 minutes(not including the drying time of the silicone) or you can jam a screw into the small pieces and skip drying time. The clicking starter sounds like the starter selenoid IS good(clicking) the starter motor itself would be my guess. Mine died a week ago, same loud click. Get someone to turn the key while you WHACK the starter motor with a hammer... Not a fix, but I know people who have had to whack the starter like once or twice a week until they finally replaced the starter.

First thing you are going to have to do is get your fuel pressure up to spec and/or make sure your pressure gage is reliable.
You may have more than one issue going on here. It all sounds familiar and I've seen most of it before, though sometimes various causes will result in the same symptoms. I've been messing with Renix's for 21 yrears now, I've run across most of the common problems.

Fuel pressure is WHAT? Should be 31 with the vacuum lone connected, or 39 without it. You changed the fuel pump? New or JunkYard?

My XJ ran like crap, a lot of the start and idle issues you mention. MY problem was the little chunk of fuel line in the tank on the pump was rotten and barely connected to the output tube. Not saying it is your trouble, but when I had proper fuel pressure, everything else went away.

neonrog said:

Fuel pressure is WHAT? Should be 31 with the vacuum lone connected, or 39 without it. You changed the fuel pump? New or JunkYard?

My XJ ran like crap, a lot of the start and idle issues you mention. MY problem was the little chunk of fuel line in the tank on the pump was rotten and barely connected to the output tube. Not saying it is your trouble, but when I had proper fuel pressure, everything else went away.

Click to expand...

x2

maxx,
you need 31 and 39, so if you have 14-15 than thats a problem with the pump, regulator, or fuel filter.

have you tried bypassing the ballast resistor? jumper/connect the two wires together leading to the resistor.

alright, retested all my fuel scenarios last night. I am sitting at like 16 PSI with key ON.

18-19PSI with motor running, vac. line to the regulator plugged in AND unplugged. I jumped the resistor and it bumped me up to like 20 PSI. I tried to pinch the return line and saw no change.

one other concern I forgot to mention: I am on my second new pump, as the first one was DOA, but when I pulled the original pump there was no rubber stopper on the end of the return. I assume it is stuck in the tray inside the tank, but I dont know what to do. I wormed it around until it felt as though it was pushed in. could this be my problem or is it another dud pump? I dont have the attachments to test pressure at the pump as opposed to the rail. otherwise I would. will try and warranty the dang pump AGAIN tonight...

maxxpehling said:

alright, retested all my fuel scenarios last night. I am sitting at like 16 PSI with key ON.

18-19PSI with motor running, vac. line to the regulator plugged in AND unplugged. I jumped the resistor and it bumped me up to like 20 PSI. I tried to pinch the return line and saw no change.

one other concern I forgot to mention: I am on my second new pump, as the first one was DOA, but when I pulled the original pump there was no rubber stopper on the end of the return. I assume it is stuck in the tray inside the tank, but I dont know what to do. I wormed it around until it felt as though it was pushed in. could this be my problem or is it another dud pump? I dont have the attachments to test pressure at the pump as opposed to the rail. otherwise I would. will try and warranty the dang pump AGAIN tonight...

Click to expand...

have you replaced the fuel filter. it could be a bad regulator. you should have a difference of 8-10 psi with the vacuum line attached and disconnected. before you put a new pump in, you should verify its not a problem with the regulator.

also, when i installed a new pump on my 89, looking down from the top, the + and - terminal posts on the new pump( + -) where opposite than on the old pump( - + ). if your pump is running in the opposite direction, this could cause low psi numbers.

I put a new filter in, and I verified my terminals on the pump. guess I'll pull it and double check my electrical and fuel connections.

how can I test the regulator? like I said there is no variance in pressure when I disconnect the vac line from it.

maxxpehling said:

I put a new filter in, and I verified my terminals on the pump. guess I'll pull it and double check my electrical and fuel connections.

how can I test the regulator? like I said there is no variance in pressure when I disconnect the vac line from it.

Click to expand...

http://www.lunghd.com/Tech_Articles/Fuel_System/Fuel_Diagnostics.htm