85 crown vic, hard starting. what do i do? help please!! - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
Ford Forum Ford Forum

» Auto Insurance
» Featured Product
ยป Wheel & Tire Center

Go Back   Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Cars and PAG Vehicles > Ford Crown Victoria | Mercury Marauder | Grand Marquis | P71
Register Home Forum Active Topics Photo Gallery Auto Loans Garage Mark Forums Read Auto Escrow

Ford Crown Victoria | Mercury Marauder | Grand Marquis | P71 Forum for discussion of the Ford Crown Victoria, Mercury Marauder, Mercury Grand Marquis and P71.

FordForums.com is the premier Ford Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 01-29-2009, 21:59   #1 (permalink)
Registered User
 
Join Date: Oct 2008
Posts: 5
85 crown vic, hard starting. what do i do? help please!!

hello i have a 1985 vic, 5.0 it has 52,000 miles and runs beautiful. the only thing that is wrong thus far is that whenever i go to start it, unless i give it a little gas it wont start on its own.?? i sea foamed it and did a tune up and fuel filter. what do i do??
cadillacmob is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 01-31-2009, 13:34   #2 (permalink)
2002 F150 XLT
 
Bert's Avatar
 
Join Date: Nov 2008
Location: Oregon
Posts: 9,856
Re: 85 crown vic, hard starting. what do i do? help please!!

When you say give it some gas, do you mean pour some in the top of the throttle body?

You should start with connecting a fuel pressure gauge to the fuel system and briefly run the engine and then turn it off. Let it set long enough for the hard starting condition to occur. Before you turn the key check the fuel pressure. If the system is sound there should be at least 20 psi residual fuel pressure. If there is less than 20psi then there is an internal system leak that has to be addressed. The next step is to watch the fuel pressure as the engine is being cranked over. The fuel pressure should jump in a blink to at least 40 psi while cranking. If the fuel pressure climbs slowly then there may be circuit resistance that is slowing the fuel pump during cranking. If all checks good then inspect the condition of the ignition spark under the same conditions. If the engine is sound and in a good state of tune, you likely have a fuel delivery or ignition problem that is present during cold start.
Bert is offline   Reply With Quote
Old 02-01-2009, 17:33   #3 (permalink)
Registered User
 
Join Date: Oct 2008
Posts: 5
Re: 85 crown vic, hard starting. what do i do? help please!!

no i have to just press the gas pedal a little for her to start. and i did the fuel pump and tank. and have good pressure. I just took it on a 120 mile trip going 74 the whole way and got 17mpg. it drives so well . just cant get that prob gone. and its a hard start cold or hot. not just on a cold start!! thanks also for the help
cadillacmob is offline   Reply With Quote
Old 02-01-2009, 20:35   #4 (permalink)
2002 F150 XLT
 
Bert's Avatar
 
Join Date: Nov 2008
Location: Oregon
Posts: 9,856
Re: 85 crown vic, hard starting. what do i do? help please!!

One thing could be problem is the TPS. It has a rheostat and maybe the spot when the pedal is closed has a problem. It has to be between ~0.6v an ~1.1V. So, ~1v is easy to remember. However, as long as the TPS is between ~0.6v an ~1.1V, it won't make any difference at all.

So, if you have a Ford TPS, a Ford TB, and the idle screw is set properly, Vref to the TPS is ~5V, then the TPS should be under ~1.1v at idle. If it is not, then you have a bad TPS. Get a new Ford TPS. Don't waste your time or money on a non-Ford TPS - they're all junk

Hook up the analog meter to the green and Black wires. With the key on open and close the throttle body slowly, you should see the needle move in a smooth arc without jumping around. If the needle jumps there is a dead spot in the TPS and it will need to be replaced.

The next step is to set the TPS to the proper voltage with the key in the on position. Using your digital meter, connect to the same wires as you did in the above. The TPS voltage should be as close to .90V with the TB in the closed position. At full open (WOT) should be around 4.5V to 4.75 V. If the TPS is not within the above settings, loosen the 2 screws and rotate the TPS until you get to .90V at closed throttle. Tighten the screws, and recheck your settings again.


Without being there that's about all I can think of.
Bert is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

  Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Cars and PAG Vehicles > Ford Crown Victoria | Mercury Marauder | Grand Marquis | P71



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -7. The time now is 11:26.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.6.0
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.