|
Post by Archangel on Feb 12, 2007 21:42:23 GMT -5
Yep, just like the title says. Took it out Monday, drove it home, parked it in the garage, and now it will not start... Here's what I've done and eliminated so far as a cause... In case you don't know my Jeep...It's a 95 YJ with a 4.0 swapped in from a 2.5. The 4.0 is from a 1990 Cherokee with the AW4 transmission complete. I also got the entire harness and ECM from the seller. Anyway... The motor will crank over all day long, however, it will not catch. First thing I checked...Spark, Fuel, Air...Had spark at the time, and I thought I had fuel...I had it at the rail at least. So, I started looking into sensors. My knock sensor is located very close to the exhaust, and I noticed it was a bit "melted", so I replaced it. I know that when I did the initial swap, it had a poor connection and the Jeep would not fire. Upon replacing the knock sensor...no fire...I went for the next logical thing....the CPS (Crank Position Sensor). Again, I found some wiring that looked questionable, so I replaced the sensor. No fire. Now, I knew I had spark and that the ECM was sending out the timing. I dumped a bit if fuel down the throttle body, and presto.... fuel + spark = fire...but not for long, once the fuel obviously burnt off, it died. I was able to do this a couple of times, and it fired every time on the first crank, so now I had narrowed it down to no fuel. I checked the pressure at the rail, and it was good. I checked the lines for air. No air. So, I began to research how the EFI system on the 4.0 worked. From what I read, the Throttle Position Sensor is in direct relation to the EFI, and it was malfunctioning, it could show the same symptoms as I am having. So, 200 bucks after the CPS and the Knock sensor, I spent 87 more on the TPS.... NO FIRE I've rechecked every inch of wire under the hood. I've checked all fuses. I've made sure the ECM is getting power and ground. I've checked all of the motor grounds to the body. I've unplugged and checked all connectors, cleaned them, and plugged them back in. NO FIRE Also, I now believe that I've lost spark. Two things brought me to this conclusion...First, I tried the gas in the TB trick again... No fire... I also noticed that when I would crank the starter over and over, my aftermarket tach would bounce a minor amount telling me that it was sparking...could be wrong on that theory, but now its stopped bouncing all together. I do not have a second person to to the spark test, so I cannot confirm this one yet. I'm starting to believe that its the ECM flaking out. First I had no fuel, and now its gone to no spark. I've found one Ebay for a reasonable price, but I hate to buy one if its not the problem. The other reason I think its the ECM, is that nothing has changed between now and Monday evening in terms of wiring, connections or anything else, and the conditions are worsening. So, who's got some ideas? Hell, at this point, I'd gladly pay someone to help me figure this out. I just want the YJ in service again.
|
|
|
Post by trebor on Feb 12, 2007 21:51:36 GMT -5
Verify spark with a timing light.Tachs work of the trigger.Fuel pressure checked with a Gage or the old sprays out of the valve thing.Low fuel pressure on fuel injection is as good as none.I heard jeeps have problems with the fuel pump relays alot.Well the xjs do i hear.
|
|
|
Post by Archangel on Feb 12, 2007 21:55:43 GMT -5
Verify spark with a timing light.Tachs work of the trigger.Fuel pressure checked with a Gage or the old sprays out of the valve.Low fuel pressure on fuel injection is as good as none.I heard jeeps have problems with the fuel pump relays alot.Well the xjs do i hear. Guess I should have said that my Fuel Pump is on a seperate circuit that I control by a switch. The ECM does not control it. I've been verifying spark by holding No. 1 wire to ground...spark... As for the fuel pressure, it is right where the book says it should be... Not arguing with you, just offering what I've already covered... this is so darn frustrating...any other ideas?
|
|
|
Post by trebor on Feb 12, 2007 21:59:07 GMT -5
try doing the ecm self test.Many have a test port you jump or ground to tell you codes .a bad ecm may say if it is bad or real bad ones won't respond to self test at all.
|
|
|
Post by Archangel on Feb 12, 2007 22:03:31 GMT -5
I'd love to, and I know most ECM's you can reset, but I cannot find where or how to do it on this particular one. I've removed the power from the system and waited, hoping it would reset...no luck
|
|
|
Post by trebor on Feb 12, 2007 22:05:45 GMT -5
I'd love to, and I know most ECM's you can reset, but I cannot find where or how to do it on this particular one. I've removed the power from the system and waited, hoping it would reset...no luck Not reset .check codes at the data port ;D
|
|
|
Post by Archangel on Feb 12, 2007 22:06:48 GMT -5
No data port on a 95 YJ with a 90 XJ 4.0
|
|
|
Post by rocncj on Feb 12, 2007 22:14:51 GMT -5
Do it have an ignition module?
|
|
|
Post by Archangel on Feb 12, 2007 22:21:35 GMT -5
Yep, sure does, and it could be that, but why did I have spark to begin with and no fuel, and now I have neither? The ECM controls the spark and fuel. Also, I have an MSD ignition triggered by the stock ignition module.... just FYI....
|
|
|
Post by rstep on Feb 12, 2007 22:26:56 GMT -5
Let's start out in left field.Did you ever find out if the battery is good? With all the cutting and splicing done are the tolerance's still good at all sensers,some ecm's get real nasty over this. Do you have any of the fuse line any where that may have blown. Have you done any welding on the rig lately with the battery still hooked up if so may have back fed current which again Ecm maybe effected.
|
|
|
Post by trebor on Feb 12, 2007 22:31:05 GMT -5
Do it have an ignition module? Had a toyota in the shop with this kind of problem and it was the ignition module.It controlled spark and told the eCm when to fire the injectors .they need to be timred together.lol worth a try.This is why i hate cars with computers.
|
|
|
Post by Archangel on Feb 12, 2007 22:31:29 GMT -5
Battery has been on a charger all day long...full power...No welding. Ecm is getting proper voltage and all sensors are seeing proper voltage and resistance...
|
|
|
Post by slick1100 on Feb 12, 2007 22:32:26 GMT -5
To pull the codes on the ECM, try turning the ignition switch "On, off, on, off, on, off, on" and count the number of times the "check engine" light flashes. It should blink something similar to morse code. If you have one, a Haynes or Chilton manual will have the codes.
|
|
|
Post by rocktoy on Feb 12, 2007 22:33:05 GMT -5
If you scabbed everything off of the '90 computer, I have a scanner that we can hook up to the plug on the ECM tomorrow, if you like. That may tell you something....not sure since you're using the MSD ignition - that may give you a false reading. Let me know, I can bring it with me.
|
|
|
Post by Archangel on Feb 12, 2007 22:33:50 GMT -5
Do it have an ignition module? Had a toyota in the shop with this kind of problem and it was the ignition module.It controlled spark and told the eCm when to fire the injectors .they need to be timred together.lol worth a try.This is why i hate cars with computers. As far as I know...in the Jeep, the ECM sends output to the ignition module and fires the injectors. Both the injectors and the ignition module are on the output side of the ECM
|
|
|
Post by trebor on Feb 12, 2007 22:34:39 GMT -5
If you scabbed everything off of the '90 computer, I have a scanner that we can hook up to the plug on the ECM tomorrow, if you like. That may tell you something....not sure since you're using the MSD ignition - that may give you a false reading. Let me know, I can bring it with me. he said he had no data port
|
|
|
Post by Archangel on Feb 12, 2007 22:35:32 GMT -5
Like I stated earlier, the data port never existed on my Jeep. To get trouble codes from the ECM, you count how many times the check engine light flashes after a certain on-off-on-off...key sequence... That held true even with the 2.5 I had... So, we've narrowed it down to an ECM or ignition module
|
|
|
Post by slick1100 on Feb 12, 2007 22:36:06 GMT -5
Another possibility is a kill switch. It would have come with one of these originally, but is surely no longer in the system. However, if it should ground out, this would kill both.
|
|
|
Post by zulu on Feb 12, 2007 22:37:39 GMT -5
It is mad at you for driving christine rubi.
|
|
|
Post by slick1100 on Feb 12, 2007 22:38:03 GMT -5
An OBDI reader wouldn't need a port per se. If you scabbed everything off of the '90 computer, I have a scanner that we can hook up to the plug on the ECM tomorrow, if you like. That may tell you something....not sure since you're using the MSD ignition - that may give you a false reading. Let me know, I can bring it with me. he said he had no data port
|
|
|
Post by Archangel on Feb 12, 2007 22:38:16 GMT -5
Another possibility is a kill switch. It would have come with one of these originally, but is surely no longer in the system. However, if it should ground out, this would kill both. Slick, thanks for mentioning this, cause I forgot to in my initial post, but thats the first thing I checked. I eliminated the kill switch from the system for the time being. No fire...
|
|
|
Post by rocktoy on Feb 12, 2007 22:38:18 GMT -5
It died before that....that's why I let him drive....tried to cheer him up!!
|
|
|
Post by rocktoy on Feb 12, 2007 22:39:13 GMT -5
An OBDI reader wouldn't need a port per se. he said he had no data port Ty says it's a Renix system, not an OBDI
|
|
|
Post by Archangel on Feb 12, 2007 22:39:47 GMT -5
An OBDI reader wouldn't need a port per se. he said he had no data port 'splain Lucy!
|
|
|
Post by trebor on Feb 12, 2007 22:42:02 GMT -5
An OBDI reader wouldn't need a port per se. he said he had no data port every obd1 i worked on had a port.It give more detailed codes than the light flashing.can the keyed self test still work on your jeep
|
|
|
Post by rocktoy on Feb 12, 2007 22:45:11 GMT -5
The 4.0 L (242 in©ø; 3956 cc) straight-6 was an evolution of the 258 and 2.5 and appeared in 1987. It had the same 3.88 in (98.4 mm) bore as the 2.5 with a longer 3.41 in (86.7 mm) stroke. The 4.0 will be discontinued at the end of the 2006 model year as the Jeep Wrangler will instead get Chrysler's 3.8 L OHV V6.
The first 4.0 engines in 1987 had RENIX (Renault/Bendix) engine control systems, which were quite advanced for their time, but are now handicapped because there are very few scan tools which can be "plugged in" to a RENIX system for diagnosis. The Renix also used a very advanced engine knocking sensor, which allowed the computer to know if detonation was occurring, thus allowing the computer to make the appropriate changes to prevent this.
The 1987 RENIX 4.0 made 173 hp (129 kW) and 220 lb-ft (298 N¡¤m) of torque. In 1988 the 4.0 received higher flowing fuel injectors, taking output to 177 hp (132 kW) and 224 lb-ft (304 N¡¤m) respectively.
In 1991 Chrysler Corporation, then the owners of the Jeep brand, redesigned the RENIX engine control computer and raised the intake ports approximately 1/8¡È for a better entry radius. Chrysler also enlarged the throttle body and redesigned the intake and exhaust manifolds for more efficiency, and the fuel injectors were once again replaced with higher flowing units. The camshaft profile was also changed. The net result of all these changes was an engine that made 190 hp (142 kW) and 225 lb-ft (305 N¡¤m) of torque. Badging on Jeeps equipped with this engine read "4.0 Litre HIGH OUTPUT". The new cam profile combined with altered computer programming eliminated the need for an EGR valve and knock sensor, but make the engine more sensitive to alterations, especially where emissions are concerned.
|
|
|
Post by trebor on Feb 12, 2007 22:45:36 GMT -5
tys right i looked it up it a renix system
|
|
|
Post by rstep on Feb 12, 2007 22:46:00 GMT -5
renix system sit's over on the pass side where all the relays are or where and you can check different reading from that point.
|
|
|
Post by trebor on Feb 12, 2007 22:47:16 GMT -5
Renix designed by the french thats the problem lol
|
|
|
Post by rocktoy on Feb 12, 2007 22:50:11 GMT -5
|
|