1998 S70 Cranks but no start.

csturner · Post by **csturner** » 24 Nov 2014, 06:58

I know you all have seen this a million times. I tried several searches and several different things. Here is the scenario.

Car sat all weekend. Started right up, went to work Monday at 1pm, no issue. Went on break, and the car would crank, but would not start. Last year, the Coolant Temp Sensor went bad, and the car was hard to start, but not dead like this.

I bypassed the fuel relay. No change.
I dumped the pressure off the fuel rail thru the Shrader valve. Cranked the engine a bit. And was able to dump more pressure off the fuel rail. I have nothing to see what the pressure was, so I guessed that if it built pressure, it must be ok.

I tried getting spark from the coil, but did not see anything. I tested the coil and it did not match the specs I found online. It was low on the resistance measurements. So I ordered a new coil and replaced it. No change.

Lacking tools, I then returned to the fuel system. When I pull the fuel supply line off the fuel rail, I only get a second of fuel before it stops again with the key in the run position. Should this be a constant flow? I have seen people drain their fuel system this way. But mine only runs for a second. Is this a bad fuel pump, or is something else telling the fuel pump to stop? Like a bad fuel pressure sensor, somewhere?

Post by **Ozark Lee** » 24 Nov 2014, 07:35

There really isn't a fuel pressure sensor on the car. The fuel pump relay primes the system for a few seconds pre-start and then turns the pump on after the car is started. If you jumper the relay the pump should run full time when the key is in position II.

You really need to get a fuel pressure gauge. Your observation that if fuel is flowing then the pump should be OK is generally true but not always. If you only have 15 or 20 PSI the system won't work. Although not totally accurate, you can use a tire gauge on the Schrader valve. If it reads 30 to 40 PSI you should be good.

Check to make sure you have spark by removing a spark plug and laying it on the head, with the wire hooked up, to see if the gap sparks. If you have spark that only leaves fuel and compression.

Doe the car sound "funny" when you crank it? Like it is spinning faster than normal? There is a somewhat rare condition where you can loose compression in all cylinders that we have dubbed the "Lawnmower Syndrome". It usually occurs after the car is started and then quickly shut back off. It is easily fixed once it is identified by dumping a teaspoon of oil into each cylinder and cranking until it starts. Unless you have determined that you don't have compression though don't apply the cure since it can make other problems worse.

If you have spark, compression and fuel pressure then you need to check for fuel injector pulses when you crank the car. That can be done with a voltmeter or by feel.

...Lee

csturner · Post by **csturner** » 24 Nov 2014, 08:12

When I get a ride back to my car, I am going to test for spark at the plugs. And I will also try to see if I can get the fuel pump to run constant, by pulling the fuel line and shorting 15 and 87 or whatever on the the relay.
Q: If I get no spark, but the coil is good? What other then the coil can cause no spark, assuming the rotor and cap are fine?

Post by **rspi** » 24 Nov 2014, 08:44

Have you scanned for codes? If you have no spark, and no fuel, you likely have a bad cam or crank sensor.

Post by **erikv11** » 24 Nov 2014, 09:08

Fuel supply sounds fine so far. I agree with the others, if no spark then almost surely a bad cam or crank sensor.

csturner · Post by **csturner** » 24 Nov 2014, 10:05

Guess I will try to see if I can get a code off of it. I have a blue tooth elm327 whatever. But I actually no longer have a android phone.

csturner · Post by **csturner** » 28 Nov 2014, 14:04

While trying to get my elm327 to connect, she started today. Now I am nervous. Issue resolved. But, I am going to get a better code reader.

Post by **rmmagow** » 28 Nov 2014, 14:54

Just connecting the thing didn't fix anything if in fact you have a problem, Check out "lawn mower syndrome" here. Common, but I've never experienced it.
If it is running now, the cam belt is OK (when was it last changed?) and fuel is maybe ok. Change the fuel filter if you don't remember or know when it was last done. New set of plugs, wires (bugicord only, Volvo plugs only) cap and rotor won't hurt. If the inside of your rotor cap is really dirty, maybe a bad seal. Come back here to talk (BOSCH only) about that. Do a black Friday code reader from , Autozone or an /Autel 702 from amazon, they will give you the "P" codes, a place to start. Simply plugging in a ELM thing didn't fix anything, you got lucky. On a 98 it's a waste of money to go deeper.
As mentioned by RSPI, cam and crank sensors are important BUT if your car sits for days at a time, patience and crank time are important too. I also own a 1998 shitbox S70 and it sits a long time between start-ups and cranking the bejeasus out of it get it running OK.
You're probably fine, use it every day and it'll run for you.

csturner · Post by **csturner** » 03 Dec 2014, 10:06

Got my new code reader today. I was only showing 4 codes, two of which have to do with the Air Pump, which I knew about. The other was the Cam Sensor and P1308
Cleared the codes, and p1308 immediately came back. I figure the Cam Sensor could be from when I disconnected it temporarily to try and start it that way. I will wait to see if it comes back.
Now I need to investigate p1308. I also need to do the Air Pump delete sometime.

Post by **erikv11** » 03 Dec 2014, 10:57

Since the code came back, it isn't from before. The bad cam sensor is why it won't start.