ANy Suggestions?
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 792
Likes: 1
From: Stanfield NC
ANy Suggestions?
The saga of the intake manifold from H**l continues. I am still in the process of installing a mini ram on my 88 L98. Most of the problems I ran into were created by TPIS and their poor machining. The holes mounting the manifold to the head on one entire side were off by 1/16th of the hole or something. Just enough that they all had to be re-worked in order to get the bolts in to the head. TPIS instrucitons leave an awful lot to the imagination and are incomplete at best. 
Upgrades included the miniram, new 24# injectors, and the elimination of the EGR set up and some of the vacume lines that are emissions related. This car is primarily a track car with very limited street miles.
The manifold is now completely installed and plumbed. Everything is ready to go, but she won't fire. It tries, but just won't go. It will pop and backfire through the intake which usually means a timing or ignition problem. We have checked everything several times. Distributer is timed at 6-8 degrees BTDC on the compression stroke. Plug wires have been triple checked for correct firing order.
What am I missing?
Upgrades included the miniram, new 24# injectors, and the elimination of the EGR set up and some of the vacume lines that are emissions related. This car is primarily a track car with very limited street miles.
The manifold is now completely installed and plumbed. Everything is ready to go, but she won't fire. It tries, but just won't go. It will pop and backfire through the intake which usually means a timing or ignition problem. We have checked everything several times. Distributer is timed at 6-8 degrees BTDC on the compression stroke. Plug wires have been triple checked for correct firing order.
What am I missing?
Burning Brakes
Joined: Aug 2004
Posts: 1,110
Likes: 1
From: Geneseo Illinois
St. Jude Donor '06
so how bad are the instructions? I despise manufacturers who put out lousy intructions. Esp. with products like the mini ram or Racetronix that have been out a while. It is simple for them to make good instructions.
How is the fuel flow in your car?
How is the fuel flow in your car?
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
Originally Posted by WNDOPDLR
The saga of the intake manifold from H**l continues. I am still in the process of installing a mini ram on my 88 L98. Most of the problems I ran into were created by TPIS and their poor machining. The holes mounting the manifold to the head on one entire side were off by 1/16th of the hole or something. Just enough that they all had to be re-worked in order to get the bolts in to the head. TPIS instrucitons leave an awful lot to the imagination and are incomplete at best.
Upgrades included the miniram, new 24# injectors, and the elimination of the EGR set up and some of the vacume lines that are emissions related. This car is primarily a track car with very limited street miles.
The manifold is now completely installed and plumbed. Everything is ready to go, but she won't fire. It tries, but just won't go. It will pop and backfire through the intake which usually means a timing or ignition problem. We have checked everything several times. Distributer is timed at 6-8 degrees BTDC on the compression stroke. Plug wires have been triple checked for correct firing order.
What am I missing?
Upgrades included the miniram, new 24# injectors, and the elimination of the EGR set up and some of the vacume lines that are emissions related. This car is primarily a track car with very limited street miles.
The manifold is now completely installed and plumbed. Everything is ready to go, but she won't fire. It tries, but just won't go. It will pop and backfire through the intake which usually means a timing or ignition problem. We have checked everything several times. Distributer is timed at 6-8 degrees BTDC on the compression stroke. Plug wires have been triple checked for correct firing order.
What am I missing?
good luck - let me know if it fires up!
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 792
Likes: 1
From: Stanfield NC
Fuel flow is good and we have 45# set as a starting point on the fuel rail. Can't fine tune the preassure until we get it running, but thought that would do it for a start up. We have turned the distributer every way but loose. Roto is pointing to the #1 cylinder SP when the timing marks are at 0 degrees and we are on the compression stroke for #1 as it blows your finger off the plug hole. We then corrected the timing to 6-8 degrees with the ESC unplugged. We have checked codes and the only code that shows is #42 for the ESC being unplugged.
Keep the thoughts coming guys. I need all the help I can get.
Keep the thoughts coming guys. I need all the help I can get.
Drifting
Joined: Apr 2003
Posts: 1,379
Likes: 4
From: rome ny
are you sure you dont have an intake port leak...it definalty sounds like you have your dist in the right positon.. it is really difficult to eyeball 6 or 8* of timing.. but if your in the general area it should fire. have you done any milling work on the heads? if you did, did you cut the front and rear of the intake?
what chip are you running.. cam? heads? tell us more info..
what chip are you running.. cam? heads? tell us more info..
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 792
Likes: 1
From: Stanfield NC
Thanks Mos90. 6-8 degrees is read with the timing light on #1 plug wire while cranking on the engine. Running stock heads & cam and there was no milling done to anything. The chip is stock. I don't hear anything that sounds like an intake or vacume leak. Would that cause a backfire through the intake? I always thought those symptoms were timing related.
Drifting
Joined: Apr 2003
Posts: 1,379
Likes: 4
From: rome ny
if you are running stock items you should be ok with chip. dont need to worry about cutting intake so thats out.. im not sure if cranking the engine will give you an accurate timing mark. i would verify that you are not 180* on your dist.. pull driver side valve cover and turn your motor to tdc just after your intake valve closes. it does sound like a timing issue at this point. if that doesnt work i work check your spark strength..
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
you'll feel pressure out of the spark plug hole on both the compression and exhaust strokes. definitely pull the valve cover and make sure the rotor is pointing to #1 cylinder AFTER the intake valve closes (with the timing pointer at 0 degrees). it really sounds like you are 180 degrees off. 
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Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Take your driver side valve cover, and spin the crank until the #1 rockers are not moving when the timing mark comes to ZERO. Then check your distributor again, I think your timing is off still, I could be wrong but it sounds just like my first MR startup
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 792
Likes: 1
From: Stanfield NC
Thought maybe we were on to something with those last suggestions. I removed the driver's side valve cover and turned the engine over till #1 intake opened and closed, lined up the timing marks and the rotor is pointing right at #1 plug in the cap. : 
Any more suggestins? Thanks to everybody so far for your thoughts.
Any more suggestins? Thanks to everybody so far for your thoughts.
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
tell us more about what you did to the engine this last go around. i'm assuming it ran previously. did you change the cam? do anything with the rocker arms? if the valves / rocker arms are way out of adjustment, you would get similar symptoms. what about the distributor? is it new? do you have an MSD box? if so, it's real easy to cross those wires up at the cap. i don't want to throw too many things out there at once. the best advice would be to back track everything you did and / or touched and try to systematically eliminate potential causes.
hang in there!!
hang in there!!
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 792
Likes: 1
From: Stanfield NC
Nothing has been changed in the valve train and the cam has not been removed. Same distributer and the car ran fine before I changed out the intake. I usually try to do these things in small increments so that it is easy to retrace the steps I took just in case there are problems like this. The 9th fuel injector is just taped up and hanging, but the car is getting plenty of gas to start up. I have been over and over everything that I did and still can't find the obvious. Went to bed thinking maybe it would scab over-heal itself-and be fine this morning. Just for what it's worth that didn't work and I didn't wake up with a SI swim suit model either. Keep the thoughts coming and thanks for all the help.
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
you mentioned having to adjust some of the mounting holes on the intake. is it possible the intake isn't seated properly against the heads? what about all of the vacuum ports on the intake - are they all plugged or connected to something? is the throttle body mounted tightly against the intake?
if you are certain the distributor is in correctly, cap is on correctly, and the wiring is correct, then i would start looking into possible vacuum leaks.
if you are certain the distributor is in correctly, cap is on correctly, and the wiring is correct, then i would start looking into possible vacuum leaks.
Intermediate
Joined: Jul 2002
Posts: 43
Likes: 0
From: sunderland ma
to varify your distributor is in correct position you will need to remove valve covers - bring yor timing mark to 0 varify both valves on #1 cyl are level - #6 should have one higher than the other - on mine the distributor cap mountings were just about 90 deg to the manifold - did you varify correct wires to injector could possibly mix up - I just replaced head gaskets on my 87 and tring to think of things that could possibly go wrong just my ideas - you can use starting fluid around outside of intake to check for leaks (rpm will rise)
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 792
Likes: 1
From: Stanfield NC
I am still at it. Everything checks out on the ignition side unless it is a cooincidental failure of some part of the ignition system.
Lets talk about vacuum leaks. The car is backfiriing through the intake. Is it possible for a vacuum leak to cause that symptom? I am an old points, condenser and carburator guy that is trying to learn all this stuff with computers and injectors. My experience says that any time a car is spitting through the intake it is ignition related, but that is with the old type setups. Is there a possability that I am looking for the wrong source of the problem and need to be looking at the intake for leaks?
Lets talk about vacuum leaks. The car is backfiriing through the intake. Is it possible for a vacuum leak to cause that symptom? I am an old points, condenser and carburator guy that is trying to learn all this stuff with computers and injectors. My experience says that any time a car is spitting through the intake it is ignition related, but that is with the old type setups. Is there a possability that I am looking for the wrong source of the problem and need to be looking at the intake for leaks?
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
i would cover that base just to be sure. much of the engine system's management is based on airflow. the back firing still has me puzzled, but like i said - start checking / eliminating all potential causes of the problem. in this case, a potential cause is anything that was associated with the removal of the old intake for the MR. this includes ignition / distributor connections and timing (which we covered), vacuum connections, intake to head mating surfaces, fuel injectors, etc.
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 792
Likes: 1
From: Stanfield NC
We are making progress here. The primary problem seems to be a vacuum leak just as many of you suggested. Seems as though the vacuum leak was significant enough that it robbed the fuel preassure regulator of enough suction to keep the fuel rails full and therefore feed the injectors. I still don't think I understand the backfiring, but it is what it is. Once we cranked the fuel pressure up all the way, the car ran-sort of. We are now on the trail of the vacuum leak and will hopefully have that fixed soon.
Thanks to everybody and especially byebyeL98 for staying with me and offeing all the suggestion and words of encouragement. Butt Ugly may be on the road this weekend afterall.
Thanks to everybody and especially byebyeL98 for staying with me and offeing all the suggestion and words of encouragement. Butt Ugly may be on the road this weekend afterall.