H.O. swap into a 90 chassis HELP!!!

[lorax81]

what is a NOID light and i will pick one up tomorrow. i will double check the grounds at the dipstick. as far as the dist i never took the cap off i just unbolted it staight out of the old block and is in the same position as my other 90 xj. that is what is so damn confusing every thing is hooked up exactly like my running xj. when i take out the plugs they are soaked with gas telling me that the injectors are letting fuel in i just cant verify that they are squirting at the right time. that is why i need a way to identify the injector wires.

the rig wont even sputter it just cranks and cranks with no fire

Well, 120 in each cylinder, you have a strong blue spark at all cylinders, and you have fuel pressure that is correct.

So, even though you have fuel pressure, is the ECU firing the injectors? Grab a NOID light and check for injector firing--test lights and multimeters won't do it. Or, you can spray ether into the intake and if it fires you will know it is the fuel injection.

Those grounds at the dipstick tube are CRITICAL. They are the grounds for the ignition control module, the ECU, and the 02 sensor.

The synch sensor in the distributor sends signals to the ECU along with the CPS/CKP that will determine the firing duration of the injectors.

Those are a few ideas for things to check.

Just to stress something simple, being 180 out on the timing has caused many XJ owners to rip out large patches of their hair. When you say firing at TDC--that is TDC on the compression stroke, i.e., the stroke where both valves are closed and if the spark plug is out there is a great force of air from the cylinder?

Not a dis, it has happened to others so I gotta ask.

 

[joe_peters]

NOID light, less than $3 at most parts stores: http://base0.googlehosted.com/base_...._SL500_AA280_.jpg&size=16&dhm=46de595e&hl=en

Look, I hate to hammer on an issue, but with wet plugs fuel shouldn't be the problem.

I am thinking along the lines of fuel/spark/compression/not at the right time, meaning that distributor needs to be indexed.

Pull all the plugs (need to get the fuel out anyway), and then bring No. 1 to TDC on the compression stroke--pull the distributor cap and see what plug it is pointing to.

A broken clock is right twice a day--if you are 180 out it will be at TDC but on the exhaust stroke.

Firing order is too young, too old, just right--15 36 24.

 

[lorax81]

NOID light, less than $3 at most parts stores: http://base0.googlehosted.com/base_...._SL500_AA280_.jpg&size=16&dhm=46de595e&hl=en

Look, I hate to hammer on an issue, but with wet plugs fuel shouldn't be the problem.

I am thinking along the lines of fuel/spark/compression/not at the right time, meaning that distributor needs to be indexed.

Pull all the plugs (need to get the fuel out anyway), and then bring No. 1 to TDC on the compression stroke--pull the distributor cap and see what plug it is pointing to.

A broken clock is right twice a day--if you are 180 out it will be at TDC but on the exhaust stroke.

Firing order is too young, too old, just right--15 36 24.

how will i know if the cylinder is on its compress or exhaust stroke, oh wait i suppose i should take the valve cover off and look at the rocker arms, or is there and easier way.

I tried ether but all it did was burn the hair off my buddies hand

and how can i be 180 out when there is no adjustment on the collar and there is no adjustment on the cap i thought that the rotor was drivin off the cam by the gear and the bottom of the shaft is what drives the oil pump

 

[lorax81]

this might sound stupid but its the only thing not renix that i am using will injectors from a 95 work with the renix components they are the light tan kind

 

[joe_peters]

Using the 95 injectors shouldn't be a problem.

Ok, make a good mark on the HB so you can see it clearly. Use a friend to crank the engine over while you keep your thumb on the No. 1 sparkplug hole in the head. ONLY on the compression stroke will there be pressure against your thumb--when you feel that pressure coming you need to stop cranking and just bring the mark to TDC, then pull the cap and check where the rotor is pointing, it needs to line up for No. 1.

 

[Slip Kid]

Using HO injectors on a Renix system will run, yet will be running very rich due to the higher flow rate. I used an a 93 intake/fuelrail/injectors. I got 11 mpg with 93 injectors running on Renix system, and it went back up to 16mpg after I swapped the Renix injectors in.

If you're using a Renix intake manifold on an unmodified 95 head, note that the fuel injectors will be partially blocked by the head ports. I've heard that it will work like this, but it is ideal to use the proper head/intake combination or to modify the head ports so they don't block the injectors.

 

[joe_peters]

Using HO injectors on a Renix system will run, yet will be running very rich due to the higher flow rate. I used an a 93 intake/fuelrail/injectors. I got 11 mpg with 93 injectors running on Renix system, and it went back up to 16mpg after I swapped the Renix injectors in.

If you're using a Renix intake manifold on an unmodified 95 head, note that the fuel injectors will be partially blocked by the head ports. I've heard that it will work like this, but it is ideal to use the proper head/intake combination or to modify the head ports so they don't block the injectors.

Disagree on the injectors. Renix are static flow 18.6 lb, 91-95 are 21 lb, not enough to make any serious difference.

 

[Slip Kid]

Disagree on the injectors. Renix are static flow 18.6 lb, 91-95 are 21 lb, not enough to make any serious difference.

That's what I figured. However I did average 11 mpg over about 20,000 miles, then I switched back to the Renix injectors, and averaged ~16mpg over 4,000 miles. Both sets are about the same age, and never had any problems in their original application.

That is enough evidence to me that it was running rich, enough that it's not worth the price of a dyno run to find the real A/F numbers.

 

[joe_peters]

That's what I figured. However I did average 11 mpg over about 20,000 miles, then I switched back to the Renix injectors, and averaged ~16mpg over 4,000 miles. Both sets are about the same age, and never had any problems in their original application.

That is enough evidence to me that it was running rich, enough that it's not worth the price of a dyno run to find the real A/F numbers.

I'll go with your word on this, as you have had practical experience with them. :cheers:

 

[lorax81]

First and foremost to everyone on this thread that put in there 2 cents and took the time to help a hillbilly in need out THANK YOU THANK YOU THANK YOU. after i swapped the injectors again and put the fuel rail back on i changed the rotor and cap for new pulled out the dist and flipped it 180 put it all back together ...............it fired rite up!!! I jumped ten feet in the air, i even danced a jig. now i believe i have a vac prob because when i give it throttle it dies. tomorrow i will check out said vac leak however if anyone has a suggestion other than vac or rotor, cap, wires,plugs(these r all new) please any info is appreciated and welcome. and if i could figure out how to post pics i would but photo bucket aint working for me any help there would be cool too


thanks j

 

[lorax81]

Okay it still aint workin. I have swapped the renix intake for the HO intake but now it wont even start. i had it started before i changed the intake. i have swapped out all the sensors for new or known functioning ones. dist is at tdc 40 psi at the rail 120 psi comp. i am lost i know it has to be somthing simple but i cant find it


J

 

[joe_peters]

Ok, before you swapped the intake it was running but would fall flat when trying to accelerate? Did you get that issue fixed before swapping the intakes?

 

[lorax81]

Ok, before you swapped the intake it was running but would fall flat when trying to accelerate? Did you get that issue fixed before swapping the intakes?

The issue was never resolved with the renix intake on. However i discovered what will make a xj fall on its face like that, its them MAP on the firewall above the valve cover. In an attempt to locate the problem i started swappin sensors from ol'blew to my other 90 xj thats a runner the only sensor that was malfunctioning was the MAP. Apparently while ol'blew sat over the summer w/out a motor a bug decided the vac hole in the map looked like a good place to lay an egg or make a home or somthing, anyways i poked it with a pick then blew it out with the air hose and works just dandy in fact it is on th runner right now along with the MAT, CPS, CKS, ECU, TPS, water sensor.

I am beginning to think that i messed something up on the chassis when i pulled the motor again for the 3rd time to easy out the rear exhaust man stud i broke off. Of course it was the one in the back that you can't get to with a regular drill. I didnt want to take the head off but i did want that thing out so i got to pull the motor trans t-case again (jeeps are fun)but i managed to somehow get the darn thing out and the motor back in but no boom boom. Im thinkin bad ground cause when i was takin it out somehow the ground wires that bolt to the dipstick got hung on and might have yanked somthing so that is where i might start tamara as everything else has to work i see gas on the plugs so the injectors are squirtn gas the plugs have spark. and all the sensors and relays are from a running rig and the ones that i took out are now in the runner and its still leave'n an oil slik down the highway. the only thing i can do now is start chasing wires at least start with the grounds.

J

 

[joe_peters]

Ok, good thinking on the grounds at the dipstick tube.

One is for the Ignition Control Module, one is for ECM, and one is for the o2 sensor.

If the ICM or ECU ground is buggered it won't run.

Multimeter time!

Good luck, it is probably an open ground circuit and you should find it pretty quick.

 

[lorax81]

on my 90 there is 5 grounds that hook to the dip stick a set of two hooked together on an eye and a set of 3 hooked together on an eye. I already replaced the O2 sensor s ground. it looked pretty bad, but the others looked fine so i guess its time to break out the multimeter.

jeeps r fun


J

 

[lorax81]

I am not getting feul out of my injedtors. I have 40psi on the rail when i am cranking but when i pull the spark plugs there is clearly no fuel on the plugs. I have chased all the wires they all look fine but I am by far a wiring genius but i which is why i choose to do this swap the "easy" way . im goin on three weeks now and the damn thing wont even fire.

 

[joe_peters]

A NOID light will confirm if there is no signal from the ECU to the injectors. Multimeters and test lights won't do. $3 most parts stores.

If you have no signal, test the CAM synch signal sensor in the distributor. If that is Ok, and there is still no injector pulse, post back and we'll take it from there.

 

[lorax81]

got a NOID test kit. of course i cannot get just one i have to buy all 8 that will be here monday is there a way to test the cam sensor I have 2 spares that came from runners.

i couldn't quite understand how to test the cam sensor from the way my chilton and or haynes were telling me

J

 

[joe_peters]

got a NOID test kit. of course i cannot get just one i have to buy all 8 that will be here monday is there a way to test the cam sensor I have 2 spares that came from runners.

i couldn't quite understand how to test the cam sensor from the way my chilton and or haynes were telling me

J

Sorry, but the best use for a Haynes or Chilton is hanging in an outhouse.

Per 90 FSM:

YOU MUST USE AN ANALOG METER:

Insert positive lead into the blue wire at the connector; insert the negative lead into the gray wire at the connector--back probe the connector, do not disconnect it.

Set the meter to the 15 volt AC scale. Turn on the key. The voltmeter should show approximately 5 volts. If there is no voltage, check your leads for a good connection. If still no volts, check for voltage at C 16 on the ECU and a good ground.

If voltage is present, check continuity between the blue wire at the distributor and C 16 at the ECU. No continuity repair harness.

Check for continuity between the gray wire at the distributor and C 5 at the ECU. No continuity repair harness.

Check for continuity between the black wire at the distributor and ground. No continuity repair harness.

Crank the engine while observing the voltmeter, the needle should fluctuate back and forth. If it does the sensor is functioning correctly.

 

[lorax81]

any suggestions on what type of meter. i am using a cheap dighital job that i am borrowing from a friend as my dad burnt up our good digital multimeter. But you say i need an analog multimeter What brand would you recomend. if im gonna buy one i want quality but I also dont have endless amounts of money to throw at this thing.

J