Bogging at low RPMs

[AllTurbo]

What's up everyone. I'm new to this forum, I just recently acquired a 92 SHO. The car was running well, but now when I am accelerating it often bogs down at low rpm's. It is particularly noticible when accelerating in first and second gears. For instance I was turning onto a busy highway from a side street, it started to accelerate then it bogged down at around 2k rpm and slowly crept up to about 3.5k rpm, after it hit 3.5k there was an engine surge and it accelerated normally. is this a common problem with the SHO's? does anyone know what could be causing this?

it runs well under normal driving conditions, pleanty of power once it's moving. It's just if I try to get on it from a dead stop, that's where the problem occurs.

it's not my clutch slipping, I am sure of this.

I'm new to domestic cars, i've always been into imports. Sadly my boosted Nissan 240sx was totaled when an 88 year old guy decided to make a turn into oncoming traffic (me). but now I get to drive an SHO while I'm rebuilding my drift machine.

Thanks for the help
Cliff

 

[Electricat]

Check for any oil in the spark plug wells. The seals around the plug wells tend to leak as these cars age, letting oil get into the wells and causing a misfire. Water in the plug wells (usually from washing the engine with a hose) can cause the same condition.

The solution is to replace the plug well seals, usually the plug wires because they are oil-soaked, and do the plugs while you are at it. Since you have already worked on imports, I assume you know that these parts for the SHO's Yahama aren't going to be cheap....

 

[revhardSHO]

Yeah its problably something ignition related. Even if its not, the plugs wires are problably due for a change anyway. A set of 6 OEM Motorcraft AGSP32FM spark plugs can be had for $23.99 @ fordpartsnetwork.com
As for plug wires, I would go with the OEM quality AC Delco wires from rockauto.com, part number 16826Q for $33.89.

The Valve cover gasket set can be had at Autozone for $72.00, I forget the part number off hand.

 

[AllTurbo]

Cool thanks, I figured it was either ignition or fuel related. I just replaced the fuel pump a few weeks ago, it was making whinning noises and sometimes the car would not start unless I banged on the gas tank. I guess I'll check out the plugs and wires today. I want to check out this engine anyway, I haven't had a chance to get up close and personal with it yet

Cliff

 

[Red Baron]

You could also try and see if your secondaries are operating properly...if they are open below 4000 RPM, that could also cause it to bog down....

 

[AllTurbo]

Holy Crap! I called Ford to see how much they wanted for plugs and wires
$215 for wires and $11 each for plugs. I bought a domestic because I thought parts would be cheaper, do most of you order the parts on the internet or do places like auto zone or pep boys carry stuff for the SHO. I always ordered parts for my nissan online, but that was because my engine came straight from Japan and was never available in the US. I figured I would have an easier time getting parts for a Taurus than i did with my other car.

 

[40BelowSummer]

I bought a domestic because I thought parts would be cheaper, do most of you order the parts on the internet or do places like auto zone or pep boys carry stuff for the SHO. .

Big mistake Parts are very expensive for the SHO. Think about it, an imported Yamaha motor made for only 6 years. For plugs I would go online, dont trust many aftermarket plugs wires. You can get Taylor 8mm spark plug wires for $84 shipped from Summit or some AC Delco ones from www.midwestsho.com You can get plugs at Autozone for about $4 a piece.

Checkers/Autozone is good for misc things like some gaskets, plugs, sensors, thermostats

but for other things check these vendors:
www.shonutperformance.com
www.midwestsho.com
www.rockauto.com
www.fordpartsnetwork.com

Good luck

heres a little list of some parts and where to get them http://www.shophoenixproject.com/lower60k/60kparts.htm

 

[SHOfun 93]

Yeah, don't let those jacked up sho parts prices from the dealership scare you away! My sho hasn't seen my local ford dealer for 4 years! I just ask the knowedgable guys on here where to get em!

 

[AllTurbo]

Yeah there was oil in my plug wells. I ordered new wires, plugs, and a valve cover gaskett set from midwestSHO. I'll check the secondary butterflys when I install all this stuff. Thanks for the help. I guess finding parts for this engine will be the same as finding parts for my nissan engine. oh well, it's all part of the game

Cliff

 

[SHO_Driver]

Also run the codes even if your check engine light isn't on. Sounds like it could be a MAF issue. Unplug the MAF and drive it, if it's better clean the MAF before you replace it. Sometimes the connector is loose or the wires get corroded.

 

[AllTurbo]

how do I check for codes on a 92 SHO, where is the ECU located? sorry for all the noob questions, I just got this car like a month ago.

 

[AllTurbo]

ok nevermind I figured out how to do it. jump the wires with a paper clip, blah blah blah...
now these are the codes I got

543 - Fuel pump monitor circuit shows no power (Service 556 code first if present) Fuel pump relay or battery power feed was open

556 - Fuel pump relay primary circuit fault


this is quite puzzeling, I replaced the fuel pump a like 2 weeks ago. I hear it come on when I start the car. if these codes were correct then it seems my fuel pump would not be getting any power, which is not the case. I can drive the car just fine, it just gets crappy acceleration at low speeds/rpms.

 

[masho95]

ok nevermind I figured out how to do it. jump the wires with a paper clip, blah blah blah...
now these are the codes I got

543 - Fuel pump monitor circuit shows no power (Service 556 code first if present) Fuel pump relay or battery power feed was open

556 - Fuel pump relay primary circuit fault


this is quite puzzeling, I replaced the fuel pump a like 2 weeks ago. I hear it come on when I start the car. if these codes were correct then it seems my fuel pump would not be getting any power, which is not the case. I can drive the car just fine, it just gets crappy acceleration at low speeds/rpms.

Most likely you are getting these codes from the old fuel pump. You need to clear the codes. IRC you just pull out the paper clip in the middle of one of the codes. I'm not sure though I use a code scanner. Clear the codes and run the car again for a while to see if they come back. Also check out the TPS (throttle position sensor) for it's output voltages with a multimeter. I gave a quick description on how do that
here.

 

[AllTurbo]

Cool thanks. I'm waiting for my plugs/wires/gasketts to come in. As I'm installing them it will give me a chance to check out a number of possibilities, without having to do things twice.

I think the major problems are coming from the plug valve gasket, there was quite a lot of oil in the wells, the plugs and wires were pretty much soaked. I am hoping that's the cause of all this, but I'm gonna clean the MAFS, check TPS, and check the secondary just to rule it out. I'm not to worried about the codes, they point to a problem that was already corrected. They should disapear in a little while, if they haven't already when i pulled the pin out.

Thanks for the help, i appreciate you guys helping out the SHO newbie

 

[masho95]

They should disapear in a little while, if they haven't already when i pulled the pin out.

Thanks for the help, i appreciate you guys helping out the SHO newbie

If you pulled the pin out at the right time, in the middle of the codes, they go away immediately.