95 MTX hesitation Issue... Maybe one for SDPATT

[SHOMA]

Okay, well I appreciate any help from anyone who can offer it, particularly SDPATT, as his SHO likely has been through it all...
I have a 95 MTX, turns over a little too long to start, once running, runs well, but at very low RPM's, taking off in 1st, or loading up 4th or 5th, it chugs/chokes, etc.. but at regular rpm's it is smooth.... Also, I lose fuel pressure at the shrader valve on top of the plenum, approx 40 mins after shut-off.....I replaced fuel filter, no change... I appreciate any help I can get! Is anyone near Springfield, MA who works on SHO's? THANKS TO ALL WHO CAN HELP!

95 MTX, Flowmasters, 17" Mille Miglia's, Clarion unit w/ dual kickers & clarion amp.....

92 Green MTX, For Sale
94 Red ATX (For Sale)
93 Green MTX (Parts vehicle)
Coming soon... 93 White ATX (for Parts)

 

[munkee]

I could be wrong (and someone please correct me if I am) but I thought that the fuel would bleed out of the lines after a while. Thats why the pump primes before you start it. Nice lookin car by the way.

<small>[ April 21, 2002, 07:23 PM: Message edited by: munkee ]</small>

 

[SHOMA]

Yes, I believe it bleeds out of the lines, to a certain extent...But if I prime the car a few key turns prior to start, it starts right up......... And while it drives/idles it is fine, unless under extreme load at low RPM's, ie taking off in 1st, or low rpm's in other gears...HELP!

 

[naval-avi8or]

It should not loose its pressure. There are three places that can result in the loss of pressure. Check valve in tank, Fuel pressure regulator, fuel injectors. If your not keeping pressure after the regulator it would mean the either the pressure regulator or injectors.

 

[sdpatt]

naval-avi8or:
It should not loose its pressure. There are three places that can result in the loss of pressure. Check valve in tank, Fuel pressure regulator, fuel injectors. If your not keeping pressure after the regulator it would mean the either the pressure regulator or injectors.

Regarding the fuel pressure, he said it.

Written descriptions are tough to understand sometimes. One man's chug is another man's miss. The chugging condition sounds more like a spark misfire. Have you checked the spark plug wells for oil and water? How old are the plugs and wires and what brand are they? What are the plugs gapped?

<small>[ April 21, 2002, 10:40 PM: Message edited by: sdpatt ]</small>

 

[SHOMA]

Thanks for looking SDPATT. Well, my father has sold cars for many years, feels it is a misfire, but is unsure. I feel it is related to the fuel issue, due to the fact that if I turn the key to cycle the pump a few times prior to startup, it starts right up, although I may have more than 1 problem. One of the vent lines by the fuel filter was putting vapors out into the air last week,due to the tank building up high pressure, and I replaced the purge valve, dont think it is doing that anymore....

BUT, as far as the spark plug wells, my previous SHO, a 94 ATX did have that, first thing I checked on this...... Bone dry, I checked a few of the front plugs, and they were gapped perfectly, the plug wires are new as well, not sure of brand... Once the vehicle is warm, it does not start well, however on initial startup in the morning, it starts INSTANTLY.... Sorry for the long post, I understand how hard it is to describe a problem! Thanks to ALL!

 

[SilverSHO]

Hey man, you're in MA...you don't have anything to worry about. I'd say about 20% of the people on this board live near you.

 

[luigisho]

Hmm... well once it warms up is certainly a clue. How old is the fuel pump? Did you check the rear plugs? Now I'm thinking faulty sensor. The car runs fine when cold/ in closed loop. How about cleaning the maf and act for good measure. Maybe start of failing cps or cid?

 

[SHOMA]

yes it starts right up when cold, however still hesitates/chokes off the line, until above low RPM's, cold or hot.... Did not check the back plugs yet, I would love to find a broken ceramic back there! I am going to try and get it scanned this week..... maybe I will get lucky, and it will say what cylinder it is at least..., or if it is a fuel issue....Cleaning the MAF AND ACT? I know where the MAF is, is the ACt in the same location? What is best to clean it with???
Thanks!

 

[luigisho]

The air charge temp. sensor is in the bottom of the air box. You can clean both with a spray electrode cleaner you can find at Radio Shack. Maf's malfunction more often than ACT's but both are easy to get to, so why not? Are you using Motorcraft plugs and wires? Is there any way to determine how old they are? I think the first thing to do is check for stored codes. You can get a cheap code reader at an auto parts store or use a piece of wire to jump the pins and read the dash light. I think you should check for codes and address any that pop up, check rear plugs, clean the accessable sensors then check back. To check what the 3 digit codes mean go to the shotimes faq under care and feeding. wink

 

[stevetatro]

Hey, 95SilverMTX,

Like luigisho said, first thing is to check for codes, both stored ones and any your car finds during the dynamic response test. While you're at it, do the cylinder balance test...lots of fun!

I had a situation very similar a few years ago. First start in the morning (or after an extended amount of down time) was great, fired right up. But, if I parked it for half an hour and tried to restart, it didn't want to. Didn't have any codes, so I lived with it for awhile.

Eventually came some drivability problems. It would run very strangely sometimes, especially when warm. Still had the same warm start problems, and no codes!

Finally, one glorious day, my CE light lit up the night sky. Ran codes, and it was a 214 (I believe). Indicated Camshaft Identification error (or some such nonsense) so I replaced the CID (Camshaft IDentification) sensor. Problems solved! Haven't had an abnormal start in 3 years (furiously knocking on wood).

I'm not recommending you throw parts at it, but it does seem CID sensors can gradually fail and wreak havoc on your SHO.

If there's no codes to be found and you want to replace the CID sensor, I think they can be found at AutoZone for around $40 and aren't too difficult to install.

<small>[ April 22, 2002, 03:58 PM: Message edited by: stevetatro ]</small>

 

[SHOMA]

Thanks to all! Stevetatro, that isnt the crankshaft position sensor is it? That was not a fun job on the last sho I had (94 ATX).... Thanks for the info! I appreciate it!

 

[SHOMA]

ANY OTHER SUGGESTIONS? I have not yet been able to have it scanned, and hope something comes up.... any other ideas? I appreciate everyone's help!!!

 

[Shoman94]

95silvermtx:
ANY OTHER SUGGESTIONS? I have not yet been able to have it scanned, and hope something comes up.... any other ideas? I appreciate everyone's help!!!

You really need to get codes first.

Jason

 

[yhardy1273]

I had same type of problem in my 89 and found out it was ignition module on intake. Mine kept making my car feel like it was missing while under load until it finally went totally out. Check it out.