home register FAQ memberlist calendar

Go Back   Turbobricks Forums > Mechanical > maintenance & nonperformance

Reply
 
Thread Tools Display Modes
Old 02-06-2019, 09:33 PM   #1
rukkus
Newbie
 
rukkus's Avatar
 
Join Date: Jan 2016
Location: ON, Canada
Exclamation 1989 740 won't start!

Hey peeps,
so I'm a relatively new owner of my 89' 740 sedan. A little background to the car, it's got a +t swap done to it by the previous owner. It runs lh2.4, and pretty much uses all factory bits and pieces. Right now theres an old leaky t3 garrett Turbo off of an 242gt I believe and uses slimmer red top injectors(#0280155759).
I've been driving it around for the first month or so with no problems regarding starting it up, only that it runs a little rich. I've been having problems with the turbo leaking abit of oil so one weekend I took it off to inspect/clean it, that night I also changed out my coolant temp sensor and swapped the fuel pump relay as a precautionary measure. Once everything was back together I go to start it and nothing. I was able to start it up with some starting fluid and 30 minutes worth of attempts. Once it starts it'll bog down and die if I add any throttle but when leaving it idle until operating temp, I can drive it around no problem.
I then went ahead to change out the main fuel pump and filter, and also the in tank pump/sender assembly since mine was all rusty/leaky.
Still no luck.
When I turn the key to the final position before cranking I do hear the pumps priming. But they don't prime every time, let's say I try to prime them every 3 seconds, 2/5 times it wont, so I'm not sure if it's reached its desired pressure or regardless it should always prime even with the short intervals.
I've also changed the radio suppression relay to rule that out, and checked whether there was a leaky fuel pressure regulator.
I still have some diagnosing to do but have had limited time lately, figured I'd post up and see if anyone's had a similar experience. (I've done some browsing through forums too).

Anyway, if you've read all of this thanks, hope to get this car back on the road asap. I'm probably forgetting some details so I'll do my best to answer any questions.
rukkus is offline   Reply With Quote
Old 02-07-2019, 01:32 PM   #2
Jesse B
Fine Modern Gentleman
 
Jesse B's Avatar
 
Join Date: Jun 2009
Location: Somerville, Ma
Default

Maybe put the old temp sensor back in and see if it starts? Maybe the new one is defective?
__________________
'73 1800ES, now converted to m41!
'89 Peugeot 505DL estate
'91 245SE
'96 855T, Autumn Gold, now converted to m56!
'11 XC70, T6
Jesse B is offline   Reply With Quote
Old 02-07-2019, 07:32 PM   #3
rukkus
Newbie
 
rukkus's Avatar
 
Join Date: Jan 2016
Location: ON, Canada
Default

Yea I'm considering retracing my steps there, but looking into it, it doesn't seem like the coolant temp sensor has any input on initial start up.
Although when I was ordering parts I noticed there was an n/a and turbocharged version. Not sure what the difference would be, but the only thing potentially wrong is I got a turbo sensor for an originally n/a block? Doesn't seem like it would cause any issues
rukkus is offline   Reply With Quote
Old 02-07-2019, 08:33 PM   #4
freevolvos
Board Member
 
freevolvos's Avatar
 
Join Date: Jan 2011
Location: hillpoint
Default

Just because it's new doesn't mean it's any good...buy a d.v.m. And start trouble shooting, of course the temp sensor has a input when it's cold..do you think it only works at 70°¿ Does it have any codes? Did you check the grounds? Is there vacuum leak? If it ran fine before it's more likely you overlooked something when you put it together....now my 240 became unbearable do drive when it went into closed loop and out ended being the 02 sensor
freevolvos is offline   Reply With Quote
Old 02-07-2019, 08:38 PM   #5
dl242gt
300+hp on the shelf club
 
dl242gt's Avatar
 
Join Date: Jun 2002
Location: S NJ, a suburb of Phila.
Default

I recently had a brand new coolant temp sensor from a supposedly reputable volvo parts supplier Uro that was totally out of spec and I had to get a good used one. So for sure get a meter and test things.
dl242gt is offline   Reply With Quote
Old 02-08-2019, 02:20 AM   #6
rukkus
Newbie
 
rukkus's Avatar
 
Join Date: Jan 2016
Location: ON, Canada
Default

Ya good point, I do have a meter, I'll definitely start trouble shooting, the free time I had I've spent on changing the pumps and such since I was planning on servicing them anyway.
But can a coolant temp sensor cause a no start situation? I initially changed it incase that was the reason I was running rich. I'll be sure to search the desired ohm readings. My old one didn't have continuity
rukkus is offline   Reply With Quote
Old 02-08-2019, 02:44 PM   #7
ZVOLV
<Master Tech>
 
ZVOLV's Avatar
 
Join Date: Nov 2002
Location: California
Default

Too long. Didn't read. Click my sig.
__________________
No Start Thread
ZVOLV is offline   Reply With Quote
Old 02-08-2019, 03:21 PM   #8
wyatt8740
Board Member
 
wyatt8740's Avatar
 
Join Date: Mar 2017
Location: Fort Wayne, Indiana
Default

It sounds like we're pretty sure it's fuel system trouble, but I just want to throw in that dying when throttling could be distributor or spark plug related, if it's been parked in rain/snow/moist envrionments.

My 244 (RIP) would do that after going through car washes occasionally until I replaced the distributor rotor and cap.

Could be it has that and other problems, too.
__________________
1991 244 (manual 5spd)
1993 245 (auto 4spd [for now])
And the Dalai Lama smiled and said, 'Well my son, life is like a beanstalk, isn't it?'
wyatt8740 is offline   Reply With Quote
Reply

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 On

Forum Jump


All times are GMT -4. The time now is 05:02 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.